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Copyright © 2007 EMC Corporation. Do not Copy - All Rights Reserved.

Symmetrix Configuration and Device Masking - 1

© 2007 EMC Corporation. All rights reserved.

Symmetrix Configuration and Device MaskingSymmetrix Configuration and Device Masking

Welcome to Symmetrix Configuration and Device Masking training.The AUDIO portion of this course is supplemental to the material and is not a replacement for the student notes accompanying this course.EMC recommends downloading the Student Resource Guide from the Supporting Materials tab, and reading the notes in their entirety.

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© 2007 EMC Corporation. All rights reserved. Symmetrix Configuration and Device Masking - 2

Course ObjectivesUpon completion of this course, you will be able to:

Describe the use of Configuration Change software to: – Create and map Symmetrix devices– Modify Symmetrix attributes

Describe the use of device masking software to allow host access to Symmetrix devices

The objectives for this course are shown here. Please take a moment to read them.




Symmetrix Configuration Change ComponentUpon completion of this module, you will be able to

Describe the functions of the Configuration Change software

Describe the process to:– Create and map Symmetrix devices– Modify Symmetrix attributes

The objectives for this module are shown here. Please take a moment to read them.




Configuration Manager OverviewExecute using the symconfigure SYMCLI command

Accessible via the Symmetrix Management Console GUI

Performs configuration changes pertaining to:– Creation and attribute modification of all Symmetrix devices including

save devices, spare devices and metadevices– SRDF group and device level characteristics– Mapping of devices to front end ports– Setting Symmetrix metrics– Setting front end port attributes

The SYMCLI Configuration Change Component, frequently referred to as the Config Manager, is invoked using the symconfigure command. It can also be invoked through the Symmetrix Management Console GUI.

Config Manager is capable of configuration operations in the Symmetrix. A few SRDF related configuration activities cannot be performed by Config Manager. These include:

Dynamic RDF group and pair creation and deletion which can be done with the symrdfcommand.Modification of dynamic RDF group parameters such as Prevent Automatic RDF Link Recovery which can be set using the symrdf command.Modify the RAs online upon Power On parameter which has to be set through the Symmetrix Service Processor using Symwin.




Symmetrix

FA

RA

Architecture

HostSYMCLI

SYMAPI

SIL

Service Processor

SYMMWIN

SYMMWINScripts

RA

Symmetrix

Ethernet Ethernet

SMC

Service Processor

SYMMWIN

SYMMWINScripts

The Config Manager architecture allows it to run Symmwin scripts on the Symmetrix service processor. Configuration change requests are generated by the symconfigure SYMCLI command or a SYMAPI library call that is generated by a user making a request through the Symmetrix Management Console (SMC) GUI.

These requests are converted by SYMAPI on the host to Symmetrix syscalls and transmitted to the Symmetrix through the channel interconnect. The Symmetrix front end routes the requests to the service processor, which invokes Symmwin procedures to perform the requested changes to the Symmetrix.

Since these scripts are the same as what a Customer Services Engineer would employ to configure the Symmetrix, Config Manager is able to do almost everything that is possible through Symmwin scripts.




Configuration Operations Classes

Device Creation

Device Conversion

Change Protection by adding/removing mirrors

Device Deletion

RDF Configuration

Manage Metadevices

Manage Save Pools

Manage spare disksMap devices to portsSet device AttributesSet device emulationSet Front end port attributesSet RDF group parametersSet Symmetrix metrics

The list shown describes the classes of configuration operations that the Config Manager can perform. For more details on the classes, please refer to Chapter 1 of the Symmetrix Array Controls CLI Guide.




Submission of Configuration Change RequestsCreate command file– Multiple commands separated with semi-colon

Commands can belong to separate classes except– Dynamic RDF changes– Save pool changes– Expanding striped metavolumes with protection

Submit file as a parameter to symconfigure

Configuration change requests are placed in a command file. The syntax for these commands is described in Chapter 1 of the Symmetrix Array Control CLI Product Guide.

Prior to Enginuity 5669, only one class of commands could be submitted for execution at one time. Though that restriction does not exist today, changes to dynamic RDF, Save pools and protected expansion of striped metavolumes can still not be mixed with other class operations in the same command file.




Stages of a Configuration ChangePreview– Verifies syntax of the command file

Prepare– Runs the Preview step– Verifies appropriateness of the requested changes against the

current state of the Symmetrix

Commit– Performs the Preview and Prepare steps– Performs the requested changes

Symmetrix lock #15 during configuration permits host I/O to flow, but blocks overlapping change requests

The Configuration Manager performs configuration changes in three steps.

The preview argument (stage) verifies the syntax and correctness of each individual change defined, their correctness as a set, and then terminates the session without change execution (correct within the realm of the host and valid as a possible Symmetrix configuration).

The prepare argument (stage) performs the preview checks and also verifies the appropriateness of the resulting configuration definition against the current state of the Symmetrix arrays; the argument then terminates the session without change execution (correct within the realm of both the host and the Symmetrix array). The prepare argument has no function for SAVEDEV pool sessions.

The commit argument (last stage) completes all stages and activates the changes in the specified Symmetrix array.

If an error is found during the preview and prepare steps, the config change session is aborted at the point where the error was found. Errors during commit are rare, since the prepare step is intended to ensure that the requested changes are valid. If errors do occur during the commit step, it is best to enlist the help of someone with access to the service processor (such as an EMC customer services engineer) to diagnose the problem and rerun the failed Symmwin script after resolving the problem.




Steps to Create a New DeviceDiscover the amount of free space available– symconfigure list –v

– symdisk list

– symdev list –da all -space

If device is to equal other devices ascertain their size– symdev list –cylinders

Verify that Symmetrix is available for config changes– symconfigure list –verify

Create a command file and use it as an argument to symconfigure– symconfigure –file <command file> -sid <SID> commit

The preparatory steps before device creation involves the use of various SYMCLI commands to discover the amount of free space on the available disks, the size of the device(s) that must be created and the availability of the Symmetrix.

A command file containing the configuration change commands is created using a text editor. Then the symconfigure command is used to make the configuration change requests.

The scope of this course does not warrant a detailed discussion of these commands. Please refer to Chapter 7 of the Solutions Enabler Array Controls guide V 6.4 for detailed Config Manager examples.




Example of a Command Filecreate dev count=4, config=2-Way-Mir, size=2300, emulation=FBA;

Logical VolumesVisible to the Host

StandardDEV001

StandardDEV002

DEV002 M2DEV002 M1

DEV001 M2DEV001 M1

2-Way-Mir

2-Way-Mir

FourHyperVolumes

Physical Disks Residingin the Symmetrix Unit

The command file shown requests the creation of four 2-Way-Mirror FBA devices of size 2300 cylinders (1 GB) each. This command file is then passed as a parameter to the symconfigure command as shown on the previous page.




Meta DeviceSeveral symmetrix volumes presented to the front-end as one device

Two types– Concatenated– Striped

A meta device is a Symmetrix mechanism for defining a device larger than the current maximum hyper-volume size. You can concatenate existing devices to form a larger meta device that is presented to the host as a single addressable device.

There are two kinds of meta devices - concatenated and striped.On a concatenated meta device, addressing of data continues to the end of a device before any data on the next device is referenced.On a striped meta device, data on meta members is addressed in user-defined stripes or chunks instead of filling an entire volume first before addressing the next volume.




ConcatenatedMeta Device

UnrelatedHyperVolumes

StripedMeta Device

MetaHead

MemberDevice

MemberDevice

MetaTail

Concatenated Meta Device on Four Physical Disk Spindles

Unprotected Striped Meta Device on Four Physical Disk Spindles

Meta Device Configurations

The meta head is the Symmetrix device recognized by the host and used for performing I/O.




Meta Device CreationThe form meta and add dev command file entries create meta devices. Specify the device to be used as the meta head, the devices to be used as the meta members, and the meta type configuration:form meta from dev 030, config=concatenated; add dev 031:033 to meta 030;

Partial list of device creation steps for meta devices

Meta RDF1

Meta RDF1+R-5

Meta RAID 6 BCV

Meta RAID 5 BCV

Meta RAID 6

Meta RAID 5

Meta Parity RAID

Meta BCV

Meta 4-Way-Mir

Desired Device Configuration

Meta 3-Way-Mir

Meta 2-Way-Mir-RDF

Meta 2-Way-Mir

Meta 2-Way-BCV-Mir

Unprotected

RAID 5

RAID 6 BCV

RAID 5 BCV

RAID 6

RAID 5

RAID-S

BCV

4-Way-Mir

Session 1 - create

3-Way-Mir

2-Way-Mir

2-Way-Mir

2-Way-BCV-Mir

→ Meta Unprotected

→ Meta RAID 5

→ Meta RAID 6 BCV

→ Meta RAID 5 BCV

→ Meta RAID 6

→ Meta RAID 5

→ Meta Parity RAID

→ Meta BCV

→ Meta 4-Way-Mir

Session 2 - form

→ Meta 3-Way-Mir

→ Meta 2-Way-Mir

→ Meta 2-Way-Mir

→ Meta 2-Way-BCV-Mir

→ Meta RDF1

→ Meta RDF1+R-5

Session 3 - convert

→ Meta 2-Way-Mir-RDF

The creation of metadevices often requires more than one configuration change session. Some require three sessions - create, form, and convert - as shown here. This table is excerpted from Chapter 1 of the Solutions Enabler Array Controls CLI Product Guide V6.4.

The form meta and add dev command file entries create meta devices. Specify the device to be used as the meta head, the devices to be used as the meta members, and the meta type configuration:

form meta from dev 030, config=concatenated;add dev 031:033 to meta 030;

These commands create a concatenated meta device using device 030 as the meta head and devices 031, 032, and 033 as the meta members.

When forming a striped meta device, specify the stripe size in number of blocks (for example, specifystripe_size=1920 for two cylinders).




Map a Device to a Port Using Config Manager Symmetrix Devices are made available on an FA port by assigning them a channel address– Referred to as mapping

Channel address is used by the host to access device– Often reflected in the c#t#d# device

naming convention– Example channel address 0003 may be

seen as c1t0d3

Devices are mapped to 2 or more ports and managed by host based path management software for– Higher Availability– Load balancing

Host

HBA HBA

Symmetrix

FA FA

00 0201 03

04 FF…

C#

T#D#

A Symmetrix can have over 64000 devices configured. Not all devices are accessed by every front-end port. Instead, specific devices are “mapped” to specific ports by assigning a channel address. Host systems discover and access Symmetrix devices using these Channel Addresses. For open systems hosts, the Channel address is the SCSI ID. Normally, a host uses a combination of the Controller, Target, and Logical Unit Number to address a disk device. The Controller number is the Host Bus Adapter, the Target is the port on the Storage System, and the Logical Unit Number is the Channel Address we assign.

The reverse of mapping a device is unmapping a device. Unmapping can become necessary prior to a device being converted from one type to another (for example, a standard to a meta member). Before the device is unmapped it has to be set not ready. The unmap action fails if the device is R/W enabled.




Steps to Map a Device to a Front-end PortIdentify FA port to which the host receiving the new device is connected– symcfg list –connections

Identify available addresses that the device could be assigned to– symcfg list –available –address -sid <SID> -sa <XX> -p<YY>

Create a command file containing the mapping request– map dev <xx> to dir <XX>:<YY>, lun=<LUN>

Execute the command file– symconfigure –file <command file> -sid <SID> commit

Before the newly created device can be used it has to be mapped to a front end port to which the receiving host is connected.

For example, the output below indicates that the host DMX800SUN1 is connected to FA 2C port 0

# symcfg list -connectionsSymmetrix ID : 000190300477Symmetrix Host

------------- -----------------------------------------------------------Director Port Node Name IP Address HW Type OS Name OS Revision-------- ---- ------------- --------------- -------- -------- -----------..........................................................................FA-2C 0 DMX800SUN1 10.127.38.35 sun4u SunOS 5.9

1 DMX800WIN1 10.127.38.33 INTEL WinNT 5.2.3790

The next command shows that LUN numbers 41 and higher are available for assignment

# symcfg list -addr -avail -sid 77 -fa 2C -p 0Symmetrix ID: 000190300477

Director Device Name Attr Address---------------------- ----------------------------- ---- --------------Ident Symbolic Port Sym Physical VBUS TID LUN------ -------- ---- ---- ----------------------- ---- --- ---FA-2C 02C 0 0020 /dev/rdsk/c2t0d0s2 VCM 0 00 000

00A9 /dev/rdsk/c2t0d1s2 0 00 001.............................................................................

00EA /dev/rdsk/c2t0d62s2 0 00 03E00EC /dev/rdsk/c2t0d64s2 0 00 040- AVAILABLE 0 00 041*




Setting Port CharacteristicsPort characteristics can be viewed by using symcfg

Port characteristics make it possible to customize the front end adapter to suit the host that connects to it– Example: HP hosts can use octal mode addressing with Volume Set

Addressing enabled

Port characteristics can be set in the command file– set port 04A:0 volume_set_addressing=enable;

Excerpt from symcfg command to view port characteristics:

DMX800SUN1/usr/sengupta> symcfg list -fa 2C -p 0 –v

......................................................

Fibre Specific Flags

{

Volume_Set_Addressing(V) : Disabled

Non_Participating(NP) : Disabled

Init_Point_to_Point(PP) : Enabled

Unique_WWN(UWN) : Enabled

VCM_State(VCM) : Enabled

OpenVMS(OVMS) : Disabled

AS400(AS4) : Disabled

Auto_Negotiate(EAN) : Disabled

}




Symmetrix MetricsMetrics that can be set with Config Manager

ENABLE or DISABLEVCMDB_restricted_accessENABLE or DISABLE (NA in 5772)raid_s_support

3 or 7 (Prior to 5771)raid_s_membersENABLE or DISABLE (NA in 5772)raid_5_support

0 to 65535rdfa_host_throttle_time0 to 100rdfa_cache_percent1-15pav_alias_limit

1 to 255max_hypers_per_diskENABLE or DISABLEhot_swap_policyENABLE or DISABLEfba_multi_access_cacheENABLE or DISABLEdynamic_concurrent_rdfENABLE or DISABLEdynamic_rdfENABLE or DISABLEconcurrent_rdf

Metric ValueMetric Name

Below is a description of some of the more commonly used Symmetrix metrics.concurrent rdf: Enables access to the concurrent RDF feature – multiple R2 devices for a single static R1.dynamic_rdf: Enables the creation of a set of devices that are RDF-capable, (can be dynamically assigned as RDF1 or RDF2 devices).dynamic_concurrent_rdf: Enables access to the concurrent RDF feature (multiple R2 devices for a single R1) for dynamic RDF devices.fba_multi_access_cache: Determines whether a read request can share cache slots in some conditions.hot_swap_policy: Indicates whether data from a failed disk should be relocated temporarily, or permanently moved to a hot spare device.max_hypers_per_disk: Specifies the maximum number of hypers that can be created on a physical disk.pav_alias_limit: If PAV is enabled, specifies the maximum number of aliases that can be assigned to a device.rdfa_cache_percent: The percentage of write pending cache that can be used by RDFArdfa_host_throttle_time: The number of seconds to throttle host writes to SRDF/A devices when cache is full, before dropping RDFA sessions.

To enable concurrent dynamic RDF the command in the command file would be:set symmetrix dynamic_rdf_configuration=Enabled;




Symmetrix Device MaskingUpon completion of this module, you will be able to

Describe requirements for connecting an Open Systems host to a Symmetrix

Make a Symmetrix device visible to a host through the use of device masking commands in Solutions Enabler

The objectives for this module are shown here. Please take a moment to read them.




Connect an Open Systems Host to a SymmetrixHBA and device drivers must be installed and configuredSAN connection between the Host Bus Adapter (HBA) and the Symmetrix front-end director port– Physical cable connection– Logical connection (zoning)

Director Port Characteristics– SCSI and Fibre Channel operating parameters– Host Operating Systems Specific

Device Mapping– Make a device visible via the front end adapter port by assigning it a target

ID and logical Unit Number

Device Masking– A single FA port can be shared by many hosts– Controls access so specific hosts see specific devices– Masking information maintained in Volume Logix Database

Before connecting an open systems host to the Symmetrix, the following questions should be answered:Which host is going to connect to which port?What are the operating systems and versions of the hosts?Number, type, and firmware levels for Host Bus Adapters (HBA)?Is PowerPath or other multi-pathing failover software used?How many, what protection, what size volumes are required?What are the Performance considerations (e.g. faster disks should be picked for high performance applications)?

On the host side, the host bus adapter (HBA) has to be configured with the correct drivers. Multi-pathing software if present needs to be set up on the host.

The physical SAN connection between the host and the Symmetrix consists of cables and SAN equipment such as Fibre channel switches. Logical zones are needed to establish a connection between the host bus adapter and the Symmetrix front end ports.

On the Symmetrix side the front end adapter (e.g. FA) needs to be cabled to the SAN and zoned such that the host HBA and the front end adapter (e.g. FA) are in the same zone. Zoning can be done using software from the SAN vendors.

The characteristics of the front end adapter port, to which the HBA connects, need to be appropriately set so the host operating system can access the Symmetrix devices. Device mapping permits a device to be accessible through a front end port. Config Manager is the appropriate tool to perform both of these tasks..

Device masking permits only a subset of devices that are mapped to a port to be visible to an HBA. This feature allows multiple hosts to share the same Symmetrix front end port without encroaching on another host’s devices. Device masking is performed using the masking commands in Solutions Enabler symmask and symmaskdb.




Fibre Channel InitializationPhysical cable connection– FA Port and the Switch– HBA Ports and the switch

When the HBA and FA ports are initialized, they log in to the switch– Identifies itself using the World Wide

Name (WWN)– Fabric Login (FLOGI)

The Initiator (HBA) queries the switch for a list of Target devices (FA ports)

The HBA logs in to the FA ports– Port Login (PLOGI)– Device discovery

Host

HBA HBA

Symmetrix

FA FA

SwitchF-port F-port

F-port F-port

FLOGIFLOGI

FLOGIFLOGI

PLOGI PLOGI

The first step in connectivity is to have a connection from the Host Bus Adapter to the FA port. This requires physical cabling and a logical path controlled by Fabric Zoning.

When the HBA and FA ports are initialized (or when the cables are connected), a Fabric Log In (FLOGI) occurs. This is a standard part of the Fibre Channel protocol where devices identify themselves to the fabric using their World Wide Name (WWN), a unique 128 bit hex identifier. The switch updates the Name Server database and assigns the device a Fibre Channel Address. After the Fabric Log In, the HBA asks the switch for the address of target devices (FA ports) and then attempts to log into each port. This is called a Port Log In or PLOGI. After the HBA has logged into the FA port, it performs a device discovery.




Display HBAs with syminq# syminq hba -fibre

Host Name : DMX800SUN2

HBA Type : FibreChannelHBA Name : Emulex-LP9002-1Vendor : Emulex CorporationModel : LP9002Serial Number : MM44136888Firmware Version : 3.90A7 (C2D3.90A7)Driver Version : 5.01e; HBAAPI v1.6.a,10-8-02Node WWN : 20000000c92ab6deNumber of Ports : 1

Port WWN : 10000000c92ab6dePort name :

/devices/pci@1f,4000/fibre-channel@2Port type : NPortPort FCID : 6436627Port speed : 2gbitSupported speed : 2gbitPort state : Online

HBA Type : FibreChannelHBA Name : Emulex-LP9002-2Vendor : Emulex CorporationModel : LP9002Serial Number : MM43015891Firmware Version : 3.90A7 (C2D3.90A7)Driver Version : 5.01e; HBAAPI v1.6.a, 10-8-02Node WWN : 20000000c93124aeNumber of Ports : 1

Port WWN : 10000000c93124aePort name :

/devices/pci@1f,2000/fibre-channel@1Port type : NPortPort FCID : 6435603Port speed : 2gbitSupported speed : 2gbitPort state : Online

This command (# syminq hba -fibre) provides more detail about the HBAs. The port WWN is used for device masking purposes. The Port Online state indicates that the FLOGI process was successful and the HBA has logged into the switch.




Displaying HBA Connections# symmask list hba -v

WWN : 10000000c92ab6de

ip Address : N/A

Type : Fibre

Adapter : pci@1f,4000/fibre-channel@2

Physical Device Path : /dev/rdsk/c2t0d0s2

Director Identification : FA-2C

Director Port : 0



Director Port : 1

WWN : 10000000c93124ae

ip Address : N/A

Type : Fibre

Adapter : pci@1f,2000/fibre-channel@1



Director Port : 0



Director Port : 1

This command (# symmask list hba –v) shows that the host from which the command was issued has two HBAs and each of them is connected (via proper zoning) to fibre ports 2C:0 and 15C:1.




Front-end Director Status# symcfg -fa all list -port -sid 77

Symmetrix ID: 000190300477

S Y M M E T R I X D I R E C T O R P O R T S

Director Port Status Connection Status

Ident Type Status P0 P1 P2 P3 P0 P1 P2 P3

FA-1C FibreChannel Online ON ON N/A N/A X X - -




Legend for Connection Status:

(X) : Fibre Port is Connected to a Fibre Port (HBA, Switch or RFDirector)

(-) : Fibre Port is Not Connected.

This command (# symcfg -fa all list -port -sid 77) shows whether a port on the Symmetrix is online and connected.




Front-end Director Details# symcfg list -fa 2C -p 0 -sid 77 –v

...........................Director Identification: FA-2C

Director Type : FibreChannelDirector Status : OnlineNumber of Director Ports : 2Director Ports Status : [ON,ON,N/A,N/A]Director Connection Status : [Yes,Yes,N/A,N/A]

Director Symbolic Number : 02CDirector Numeric Number : 34Director Slot Number : 2

Director Port: 0

WWN Node Name : 5006048AD5F04F41WWN Port Name : 5006048AD5F04F41

Fibre Channel Loop ID : N/AFibre Adapter Type : N/A

...........................

This command (# symcfg list -fa 2C -p 0 -sid 77 –v) displays detailed information about the port. The example here is an excerpt from the output that describes the readiness of the director and its world wide node and port names. The symcfg command can also be used to place a director on and offline.

Example:

symcfg -SA 2C -p 0 -sid 77 online




Port Flags Support Different Hosts and O/S# symcfg list -fa 2C -p 0 -sid 77 –v

...........................SCSI Flags

{Negotiate_Reset(N) : DisabledSoft_Reset(S) : DisabledEnviron_Set(E) : DisabledHP3000_Mode(B) : DisabledCommon_Serial_Number(C) : DisabledDisable_Q_Reset_on_UA(D) : DisabledSunapee(SCL) : DisabledSiemens(S) : DisabledSequent(SEQ) : DisabledAvoid_Reset_Broadcast(ARB) : DisabledServer_On_AS400(A4S) : DisabledSCSI_3(SC3) : DisabledSPC2_Protocol_Version(SPC2) : DisabledSCSI_Support1(OS2007) : Disabled

}

Fibre Specific Flags{Volume_Set_Addressing(V) : DisabledNon_Participating(NP) : DisabledInit_Point_to_Point(PP) : EnabledUnique_WWN(UWN) : EnabledVCM_State(VCM) : EnabledOpenVMS(OVMS) : DisabledAS400(AS4) : DisabledAuto_Negotiate(EAN) : Disabled

}...........................

Displayed here is a continuation of the previous slide’s command output. SCSI and Fibre flags are designed to support a wide variety of hosts. These flags are enabled or disabled using the Config Manager.

Protocols used to communicate between hosts and storage systems are designed to support a wide variety of applications and operating system requirements. SCSI is a standards-based protocol that has been around for over twenty years and the command set and nexus is flexible enough to support many different types of storage devices and host operating systems. Nearly every server vendor supports SCSI; unfortunately, not every vendor implements SCSI in exactly the same way. For example, while HP-UX and IBM AIX support the SCSI protocol, they support a different subset of the operational parameters. Fibre Channel and IP are transport protocol used with the SCSI protocol and also have a number of configurable protocol and link parameters.

The emulation code in the Symmetrix front-end director port is implemented in software. This allows the director to be configured to suit a wide variety of hosts and operating systems. The settings are called port flags.




Switch Perspective - Fabric Login Root> show zoning

Default Zone Enabled: False

Zone Set: All_in_one_ZoneSet

Zone: DMX3_HP3A

Zone Member: 50:06:04:8A:CC:C8:3E:0F

Zone Member: 50:06:0B:00:00:07:79:1A

Zone: DMX3_HP3B

Zone Member: 50:06:04:8A:CC:C8:3E:00

Zone Member: 50:06:0B:00:00:07:7F:36

Zone: DMX3_IBM3A

Zone Member: 10:00:00:00:C9:25:44:B7

Zone Member: 50:06:04:8A:CC:C8:3E:20

.................................................

Connectivity status can also be verified by logging into the fibre channel switch. When an HBA or FA port is connected to the switch, it identifies itself by its WWN and specifies operating parameters (such as buffer credits, link speed, and class of services), and is assigned a Fibre Channel address.

The example shows HBA and FA ports logged into the switch. Please note that the example is for a McData switch, but other vendors have commands that provide similar information.




Device MaskingDevice maskingallows multiplehosts to effectively share the same front-end ports– FA port can “see” up to 256 HBAs

Restrict access to specific host and/or host clusters

Implemented in theSymmetrix with Volume Logix– Fibre Channel– iSCSI

FC Switch

Host A

HBA HBA

Host B

HBA HBA

Host C

HBA HBA

Host D

HBA HBA

Host X

HBA HBA

Host Y

HBA HBA

Host Z

HBA HBA

VCMDB

Symmetrix

FA or SEp0 p1

FA or SEp0 p1

Storage Area Networks provide a fan-out capability where it is likely that more than one host is connected to the same Symmetrix port. The actual number of HBAs that can be configured to a single port is operating system and configuration dependent, but fan-out ratios as high as 256:1 are currently supported. Reference the support matrix for specific configuration limitations.

Each port may have as many as 4096 addressable volumes presented. When several hosts connect to a single Symmetrix port, an access control conflict can occur because all hosts have the potential to discover and use the same storage devices. However, by creating entries in the Symmetrix’s device masking database (VCMDB), it is possible to control the volumes “seen” by a host.

Device Masking is independent from zoning, but zoning and masking are typically used together in an environment. Zoning provides access control at the port level. It establishes a logical connection between the host bus adapter and port on the storage system. Device masking allows a subset of volumes mapped to a port to be visible to the host bus adapter.

With Fibre Channel, Device Masking uses the UWWN (Unique Worldwide Name) of Host Bus Adapters and a VCM database device. In iSCSI, the iSCSI Qualified Name (IQN) is used. Regardless of the protocol, the concepts are the same. The device-masking database (VCMDB) on each Symmetrix unit specifies the devices that a particular WWN or IQN can access through a specific Fibre port.




Volume Logix Database - VCMDBDatabase types are Symmetrix model specific and sized to handle the maximum number of logical volumes – Originally a separate Symmetrix Logical Volume– Starting with the DMX-3, it is stored in the Symmetrix File System

VCM DB is maintained using Solutions Enabler symmask and symmaskdb commands

Solutions Enabler accesses the VCM database using a VCM gatekeeper device– VCM gatekeeper is host accessible– The SFS is not directly accessible– VCM GK only needs to be mapped

to the management host

Symmetrix File System Symmetrix File System

VCM GK

VCM GK

VCMDBManagement Host

The Volume Logix Database persistently maintains the device masking information. Originally, the database was located directly on a Symmetrix Logical Volume. On DMX-3 it is maintained in the Symmetrix File System (SFS). Rather than create the actual VCMDB device, we now create a VCM Gatekeeper device which is used by the Solutions Enabler to access the database on the SFS, as the SFS volumes are not host addressable. The VCM Gatekeeper is a 6-cyl device.

By default, the device masking VCMDB is accessible to all HBAs that log into the director port where the database is configured. Thus, any host with access privileges can effectively modify the contents of the database if it has device masking commands installed. Beginning with Enginuity Version 5670, the VCMDB can be unmapped from any director that is not being used for masking control.




Example:– HBA0 WWN -> FA03a:0 - dev 000-010– HBA0 WWN -> FA14a:0 - dev 000-010– HBA1 WWN -> FA03a:0 - dev 000-010– HBA1 WWN -> FA14a:0 - dev 000-010

Entries in the VCMDB define relationship between masked connections and devices– FA consults VCMDB to resolve access rights

Same approach for both FC and iSCSI

Connection Records Maintained in VCMDBHost AHBA0WWN

HBA1WWN

Symmetrix

FA3a:0 FA14a:0

00 0201 …

VCMDB

Device Masking controls host access to a set of devices by maintaining a set of entries in the VCMDB on the array that defines the relationship between masked connections and devices. These entries are sometimes called initiator records.

Each entry includes a host's HBA identity (WWN or iSCSI Qualified Name), its associated FA port, and a range of devices mapped to the FA port that should be visible only to the corresponding HBA.

Once you make this VCMDB entry and activate the configuration, the Symmetrix makes visible to a host those devices that the VCMDB indicates are available to that host's initiator through that FA port.

Volume Logix is the brand name for the software in the Symmetrix that performs the device masking function. The capability is built into Enginuity, but its use is optional.




Set-up Device Masking There are four steps in setting up device masking on the Symmetrix

1. Configure a VCM gatekeeper device2. Set the VCM attribute for the device3. Set the VCM flag for front-end director port4. Assign the VCM gatekeeper to front-end port

After the VCM is setup, the database is maintained using the SE symmask and symmaskdb commands

– Add and remove masking entries– Initialize, query, backup, and restore database – May also be configured with EMC ControlCenter or SMC– External configuration locks are used to coordinate updates

Typically performed when the bin file is initially created

To set-up device masking, a database volume (VCMDB) must be created and flags must be set on the Fibre Channel or iSCSI ports to enable use. Once the database is setup and enabled, the Solutions Enabler symmask command can be used to configure entries granting specific hosts access to specific volumes.

During the execution of the symmask or symmaskdb commands, the SYMCLI sets a Symmetrix External Lock on the Symmetrix where the device masking database (VCMDB) resides. This lock ensures that only one host can make changes to the database at any one point in time. If, during the processing of a symmask or symmaskdb command, the host fails or a Ctrl/C is performed in the middle of the command, the lock might not release and could lock out further needed changes or control actions. If a device masking command is interrupted and the lock is not released, future invocations of a device masking command displays the following error message: The operation failed because another process has an exclusive lock on the local Symmetrix.

To further examine the presence of this lock, use the following form:

symcfg -sid SymmID list -lock -lockn ALL

The command will list Symmetrix external locks being held. For masking commands the lock number is 14. The lock can be released with the command:

symcfg -sid SymmID -lockn 14 release




DiscoveryThe symmask discover hba command– Verifies VCM is enabled for port– Identifies paths to the VCMDB– Assigns alias names to the HBAs AWWN

Host AHBA0WWN

HBA1WWN

Symmetrix

FA3a:0 FA14a:0

00 0201 …

VCMDBVCMGK

C:\>symmask discover hba

Symmetrix ID : 000190102254

Device Masking Status : Success

Identifier Type User-generated Name

---------------- ----- -------------------------------

10000000c93da44a Fibre W2K3-39-106/10000000c93da44a10000000c93da45c Fibre W2K3-39-106/10000000c93da45c

C:\>symmask discover hba


Device Masking Status : Success

Identifier Type User-generated Name

---------------- ----- -------------------------------

10000000c93da44a Fibre W2K3-39-106/10000000c93da44a10000000c93da45c Fibre W2K3-39-106/10000000c93da45c

The symmask discover command can be run on the management host and/or other attached hosts. The symmask discover identifies paths to the device masking database (VCMDB) and assigns alias names (AWWN/AISCSI) to the HBAs residing on the host where the command was executed.

When the symmask discover finds a host HBA, it reads the login history table and checks whether an alias exists in the device masking VCMDB. If one does, this command writes it to the login history table. If there is no alias in the device masking VCMDB record, or the login history table, it creates an ASCII alias and writes it to the login history table.

Next, it outputs the initiator identifier (WWN/iSCSI) of the HBAs that are connected to the masked channel and Symmetrix array.

Alias names can be used in the command line, replacing the cumbersome numeric identifiers. These names, which are stored in the Symmetrix array’s login history table, identify the HBAs connected to the network interface. Alias names can be shorter in length and much more recognizable than the cryptic WWNs/iSCSIs.

ASCII alias names generated by the discover action consists of two parts: the name of the host and the name of the HBA. For example: the AWWN for a host whose TCP/IP hostname is john4554b, on adapter 10000000c920cf87, would be john4554b/10000000c920cf87.




Initialize and Format the VCMDB Database# symmaskdb list database

The Symmetrix device masking database has not been initialized

C:>symmaskdb init -file VCMdbBackup070707

Initialize Symmetrix SymMask database on Symmetrix 000190100172 (y/[n])? y

Symmetrix SymMask database on Symmetrix 000190100172 initialized

C:>

# symmaskdb list database

The Symmetrix device masking database has not been initialized

C:>symmaskdb init -file VCMdbBackup070707

Initialize Symmetrix SymMask database on Symmetrix 000190100172 (y/[n])? y

Symmetrix SymMask database on Symmetrix 000190100172 initialized

C:>

During the initial setup of any device masking environment, the database has to be initialized. To check whether the VCMDB has already been initialized and already contains records, issue the command::

symmaskdb list database

To initialize and clear the VCMDB database, you must specify a backup file name to safeguard against clearing data in the database that should not be lost. For example, the following command creates a file called MyInitBackup and attempts to write any current data to it prior to initializing and formatting the VCMDB:

symmaskdb init –file MyInitBackup

Note:

The Solutions Enabler device masking function requires a license key. This is installed using the symlmf command.




Add HBA Access to Symmetrix Devices - 1C:> symmask list hba

Identifier Type Adapter Physical Device Path Dir:P

---------------- ----- ---------------- ------------------------ -----

10000000c9274156 Fibre i@1f,4000,@2 Physicaldrive0 7A:0

Physicaldrive1 7A:0

10000000c92741a1 Fibre i@1f,4000,@4 Physicaldrive2 8A:0

Physicaldrive3 8A:0

C:> symcfg list -FA 7a -addr

Symmetrix ID: 000190100172 (Local)

Director Device Name Attr Address ---------------------- ----------------------------- ---- --------------

Ident Symbolic Port Sym Physical VBUS TID LUN

------ -------- ---- ---- ----------------------- ---- --- ---

FA-7A 07A 0 0040 Not Visible 0 00 000 0041 Not Visible 0 00 0010042 Not Visible 0 00 0020043 Not Visible 0 00 0030044 Not Visible 0 00 004

C:> symmask list hba

Identifier Type Adapter Physical Device Path Dir:P

---------------- ----- ---------------- ------------------------ -----

10000000c9274156 Fibre i@1f,4000,@2 Physicaldrive0 7A:0

Physicaldrive1 7A:0

10000000c92741a1 Fibre i@1f,4000,@4 Physicaldrive2 8A:0

Physicaldrive3 8A:0

C:> symcfg list -FA 7a -addr

Symmetrix ID: 000190100172 (Local)

Director Device Name Attr Address ---------------------- ----------------------------- ---- --------------

Ident Symbolic Port Sym Physical VBUS TID LUN

------ -------- ---- ---- ----------------------- ---- --- ---

FA-7A 07A 0 0040 Not Visible 0 00 000 0041 Not Visible 0 00 0010042 Not Visible 0 00 0020043 Not Visible 0 00 0030044 Not Visible 0 00 004

When configuring device masking, three pieces of information are needed:

The World Wide Port Number for the Host Bus Adapter(s).

The number of the front end director and port to which the HBA is connected, e.g. director 7A port 0

List of Symmetrix devices that are mapped to the port. Available devices are those that have a channel address assigned.

The symmask list hba command displays the WWN for each HBA in the host. It also displays the director and port of the connection to the Symmetrix and the device file for the gatekeeper device.

In the example shown the host has two HBAs: one with the WWN of 10000000c9274156, and the other 10000000c92741a1.One HBA is connected through director 7a port0 and the other through 8a por0.

The symcfg list –FA 7A –addresses command displays a list of devices mapped to that port starting with Symmetrix logical volume 40.




Add HBA Access to Symmetrix Devices - 2

C:> symmask add dev 40,41,42 -wwn 10000000c9274156 -dir 7a -p 0

C:> symmask add dev 40,41,42 -wwn 10000000c92741a1 -dir 8a -p 0

C:> symmask refresh

Refresh Symmetrix FA directors with contents of SymMask database000190100172 (y/[n]) ? y

Symmetrix FA directors updated with contents of SymMask Database000190100172

C:>

C:> symmask add dev 40,41,42 -wwn 10000000c9274156 -dir 7a -p 0

C:> symmask add dev 40,41,42 -wwn 10000000c92741a1 -dir 8a -p 0

C:> symmask refresh

Refresh Symmetrix FA directors with contents of SymMask database000190100172 (y/[n]) ? y

Symmetrix FA directors updated with contents of SymMask Database000190100172

C:>

The symmask command shown masks devices 40 through 42 to the specified HBAs through directors 7A port 0 and 8A port 0 respectively.

The symmask refresh command updates the access control tables in the directors with the new information after the changes are made.




The Case for Using for LUN offsetMore than one host sharing an FA port

Each host is assigned a different subset of devices through device masking

LUN offset is used when– Both hosts need a LUN 0 OR– A host needs to see contiguous LUN addresses though the devices

in the Symmetrix are non-contiguous

LUN offset is an enhanced visibility feature that allows any host type to adjust host visibility by offsetting (renumbering) LUN addresses. This is useful for host types that need to see LUN 0000 or transform a noncontiguous LUN sequence to a contiguous sequence. In a case where two hosts access the same Symmetrix director port and need to see a LUN 0000 - but not the same device, you can use LUN offset. This is used so that one host sees the devices mapped from LUN “x” as starting from LUN 0000, and the other host sees devices from LUN “y” as starting from LUN 0000.

To account for noncontiguous device LUN addresses, specify a LUN base and offset as hexadecimal values to adjust for the break in the LUN sequence. The base hex value represents the first LUN in a renumbered LUN sequence. The offset hex value added to the base value determines where to begin renumbering. For example, if a host needs to detect LUN 0000, but you want your host to detect only LUNs 0005 through 0008, you can specify a LUN base address of 0000 and an offset of 0005.

The use of the Solutions Enabler symmask command is discussed later in this module, but below is an example of a command to renumbers LUNs 0005 through 0008 as LUNs 0000 through 0003:: symmask set lunoffset on 0005 0000 –dir 16A -p 0 –wwn 10000000c920b484




Example: Hosts share a Front-end Port A Linux and a Windows host share same FA port

# symcfg list -connections


Symmetrix Host

------------- -----------------------------------------------------------

Director Port Node Name IP Address HW Type OS Name OS Revision

-------- ---- ------------- --------------- -------- -------- -----------

......................................................................

FA-15C 0 DMX800WIN1 10.127.38.33 INTEL WinNT 5.2.3790

0 DMX800LIN1 127.0.0.1 i686 LINUX 2.6.9-34.E

1 DMX800SUN1 10.127.38.35 sun4u SunOS 5.9

FA-16C 0 DMX8HP1 10.127.38.39 9000/800 HPUX B.11.23

......................................................................

The output of the symcfg list –connections –sid 77 shows that both a Linux host and a Windows host are connected to director 15C port 0 on Symmetrix 77.




10 data devices are mapped to director 15C port 0# symcfg list -addr -sid 77 -dir 15c -p 0Symmetrix ID: 000190300477

Director Device Name Attr Address---------------------- ----------------------------- ---- --------------Ident Symbolic Port Sym Physical VBUS TID LUN------ -------- ---- ---- ----------------------- ---- --- ---FA-15C 15C 0 00ED Not Visible 0 00 000

00EE Not Visible 0 00 00100EF Not Visible 0 00 00200F0 Not Visible 0 00 00300F1 Not Visible 0 00 00400F2 Not Visible 0 00 00500F3 Not Visible 0 00 00600F4 Not Visible 0 00 00700F5 Not Visible 0 00 00800F6 Not Visible 0 00 00900F7 Not Visible 0 00 00A

..............................................................................

Scenario for Using LUN Offset

The output of the command symcfg list –addresses –sid 77 –dir 15C –p 0 shows that devices ED through F7 are mapped to director 15C port 0 as LUNs 0 through A.




Setting Base and OffsetIf Linux host needed a LUN 0 a LUN offset could be set:– symmask –sid 77 set lunoffset on 7 0 –awwn <awwn of Linux HBA> -dir 15C –p 0

After setting the offset, devices F4 through F7 appear as LUNs 0 through 4 to the Linux host

7000007 – 00ADevs F4:F7

000 – 006Devs ED:F3

OffsetBaseLinux host LUNs

Windows host LUNs

As shown in the table, devices 0ED through 0F3 could be made visible to the Windows host as LUNs 0 through 6. This requires no LUN offset because these devices are in fact mapped to the Symmetrix front end port as LUNs 0 through 6.

By setting the LUN offset for the Linux host to 7, devices F4 through F7 are visible to the Linux host as LUNs 0 through 4.




Setting Skip AdjustmentIf Windows host needs contiguous LUNs while addressing devices ED : EF and F4:F5– symmask –sid 77 set lunoffset on 3 4 –awwn <awwn of W2K HBA> -dir 15C –p 0

Linux host needs LUN 0 while addressing devices 03 : 06 – symmask –sid 77 set lunoffset on 0 3 –awwn <awwn of Linux HBA> -dir 15C –p 0

3000003 – 006Devs F0:F3

4003007 – 008Devs F4:F5

000 – 002Devs ED:EF

OffsetBaseLinux LUNs

Windows LUNs

Here the Windows host has visibility to devices ED through EF as LUNs 0 through 2, without the use of LUN offset. By assigning a base of 3 and an offset value of 4, devices F4 and F5 appear to be LUNs 3 and 4 to the Windows host.

In the case of the Linux host, the base of 0 and offset of 3 allows the host to view devices F0 through F3 to appear as LUNs 0 through 4.

It is not possible to have more than one skip hole covered by LUN offsets.




Dynamic Addressing with 5772 and SE 6.4When devices are mapped to front-end ports, a channel address is assigned

The LUN address can be specified in the connection record overriding the mapped address

Allows each host sharing a port to used the same addresses to access different devices

Example:symmask add devs 15,18,20 -lun 0 -wwn 20000000c920b484 -dir 14C -p 1

Host A

HBA HBA

Symmetrix

FA FA

00 0201 03

04 FF…

Host B

HBA HBA

Host C

HBA HBA

Dynamic LUN addressing is more convenient than using LUN offsets. If dynamic LUN addressing is used, using LUN offsets is no longer permitted. However, it is only supported on Enginuity 5772 and Solutions Enabler 6.4

When adding devices you can specify the starting LUN address for each device using the -lun option. Or have SYMAPI assign the LUN address using the -dynamic_lun option.

-lun = Specifies starting LUN addresses. You can specify a single starting LUN or multiple LUNs to match the given ranges. For example:

symmask add devs 15,18 -lun 0 -wwn 20000000c920b484 -dir 4C -p 1

-dynamic_lun = Specifies the use of dynamic LUN addressing. The application assigns the addresses based on what is already in use for the host HBA.-

symmask add devs 2C,2E,30 -dynamic_lun -wwn 20000000c920b484 -dir 2a -p 1




Setting HBA Port FlagsSupported in SE 6.4 and later (supersedes heterogeneous host configuration)

Host flags enabled or disabled on per initiator basis

Example– symmask –sid <sid> set hba_flags on C, SC3 –enable –wwn <wwn of HBA> -dir <dir> –p <port #>

SCSI_Support1 [OS2007]SPC2_Protocol_Version [SPC2]Avoid_Reset_Broadcast [ARB]Sequent [SEQ]Volume_Set_Addressing [V]Sunapee [SCL]Siemens [S]SCSI_3 [SC3]Environ_Set [E]OpenVMS [OVMS]Disable_Q_Reset_on_UA [D]AS400 [AS4]Common_Serial_Number [C]

This feature allows specific host flags to be enabled or disabled on a director port and permits heterogeneous hosts to share a single director FA port even though they may require different port settings for their distinctive interface protocol.




Display the Contents of the VCMDBC:> cd \Program Files\EMC\SYMCLI\bin

C:> symmaskdb list database


Database Type : Type6

Last updated at : 01:40:29 PM on Thu Sep 01,2007

Director Identification : FA-7A

Director Port : 0

User-generated

Identifier Type Node Name Port Name Devices

---------------- ----- --------------------------------- ---------

10000000c92741a1 Fibre 10000000c92741a1 10000000c92741a1 0040:0042

C:> cd \Program Files\EMC\SYMCLI\bin

C:> symmaskdb list database


Database Type : Type6

Last updated at : 01:40:29 PM on Thu Sep 01,2007

Director Identification : FA-7A

Director Port : 0

User-generated

Identifier Type Node Name Port Name Devices

---------------- ----- --------------------------------- ---------

10000000c92741a1 Fibre 10000000c92741a1 10000000c92741a1 0040:0042

You can display the entire contents of the VCMDB or use options to restrict the display to your area of interest. In the example above we are displaying access control records for the entries we previously added. Note: the entire output is not displayed.

You can restrict the output to a specific HBA. For example:

symmaskdb -list devs -wwn 10000000c9238053

You can also view which HBAs have been assigned to specific devices. For example:

symmaskdb list assignment -dev 0040:0043




VCM Database MaintenanceAccess control is tied to the WWN of an HBA

If a HBA fails and must be replaced, the VCMDB must be updated to reflect the change– Example:symmask –wwn 20000000c920b484

replace 20000000c920b393

– Updates all masking records

Backup the VCM database– Periodically and before making changes– Example:symmaskdb –sid 123 –file VCM_backup073007 backup

Because device masking is tied to the WWN of an HBA, if it must be replaced, the VCMDB must be updated to reflect the new WWN.




Module SummaryKey points covered in this module

Requirements for connecting an Open Systems host to a Symmetrix

Making a Symmetrix device visible to a host through the use of device masking commands in Solutions Enabler

These are the key points covered in this module. Please take a moment to review them.




Course SummaryKey points covered in this course:

Use of Configuration Change software to – create and map Symmetrix devices– modify Symmetrix attributes

Use of device masking software to allow host access to Symmetrix devices

These are the key points covered in this training. Please take a moment to review them.

This concludes the training. Please proceed to the Course Completion slide to take the assessment.

r Mr Xwp Symcfgmsk Srg

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