Silverton Consulting, Inc. StorInt™ Briefing - WordPress.com ·...

Introduction In today’s challenging IT environment, customers are demanding high accessibility and business continuity for many of their systems so that they can continue to operate without any downtime. For these systems, IBM® z/OS® has always been regarded as the premier operating system for the most mission-‐critical activities, and deservedly so.

In addition, as information needs continue to grow exponentially, some applications are generating and using vast quantities of data. Many mainframe customers have turned to virtual tape as a way to economically store and manage these massive amounts of data.

In response, IBM introduced the IBM Virtualization Engine™ TS7700 to address System z® application requirements for prodigious amounts of data and high data availability. In fact, the TS7700 Virtualization Engine offers the performance of online disk with the recoverability and immense capacities of virtual tape, which is impossible to achieve with current DASD solutions alone.

Enterprise business continuity and disaster recovery challenges Most large enterprises use more than one data center spread across locations to distribute workload activity and support IT requirements for business continuity and disaster recovery (BC/DR). System z helps to make such multisite facilities much easier to deploy and manage.

Nonetheless, one continuing challenge to the more widespread adoption of multisite BC/DR capabilities is that data can usually reside only in one place and normally is accessible from only that location. While z/OS can replicate data across sites and applications can access data from different locations using System z, these capabilities can be difficult and time consuming to exploit.

Early on, IBM created synchronous DASD replication to enable mainframe system users to sustain business continuity and to provide disaster recovery in the face of site outages. Over time, IBM added Hyper Swap®, DASD Global Mirror and System z Geographically Dispersed Parallel Sysplex™ (GDPS®) automation to support faster recovery response times in case of equipment, site or regional outages.

However, the System z BC/DR capabilities discussed above typically require serious consideration prior to use. Before invoking GDPS, customers had to weigh the disadvantages of accessing data and executing systems at other locations with the advantages of continuing to operate, albeit in an impaired fashion, at the primary site. Similar concerns hold for HyperSwap as well. After a disaster, moving applications and data

Silverton Consulting, Inc. StorInt™ Briefing

IBM VIRTUALIZATION ENGINE TS7700 PAGE 2 OF 10

TWITTER.COM/RAYLUCCHESI | RAYONSTORAGE.COM | +1-720-221-7270 | SILVERTONCONSULTING.COM

© 2012 SILVERTON CONSULTING, INC. ALL RIGHTS RESERVED

back to the primary site requires extensive coordination between locations. On top of that, when applications and data return to the primary site, customers need to reinitiate data replication to prepare for the next outage. Although z/OS can facilitate much of this activity, it still takes a lot of time and effort to perform properly.

At the present time, two-‐site and three-‐site BC/DR configurations are the most common. Some larger organizations are even starting to consider deploying four-‐site BC/DR topologies. With four-‐site environments, disaster scenarios will increase several times over, causing the complexities encountered with current two-‐ and three-‐site BC/DR solutions to become even more of a hindrance.

Tape, tape automation and virtual tape in System z The ancestors of System z evolved during the heyday of very expensive DASD and relatively inexpensive tape. As a result, tape storage has been an integral part of the mainframe environment since the start of computing in the middle of the last century.

With the addition of tape automation in the form of libraries in the 1980s and 90s, one could argue the predecessors of z/OS increased tape usage beyond historic levels. In those decades, many applications used automated tape rather than DASD to host large quantities of data and to benefit from the reduction in operational expense available from tape libraries.

Virtual tape, which uses both disk and physical tape to hold customer data, also made its first appearance in mainframe environments. With tape data being so prevalent in System z, it was no surprise that combining disk and tape into one automatic, self-‐contained system could optimize the use of both technologies. Tape virtualization capabilities were able to provide the access times of disk with the economics and scalability of tape.

Another significant advantage introduced by the precursors of z/OS was the automated policy management of customer DASD and tape data. Even today, advanced data policy management functionality is mostly missing from open distributed systems, and, where present, they still lack the synergistic integration of these facilities across all supported infrastructure.

IBM continues to innovate in tape, tape automation and virtual tape systems and is currently the leading provider of tape drives and virtual tape solutions to enterprise customers. In fact, IDC currently ranks IBM as

• #1 in Enterprise Tape Drive Market Share, • #1 in Enterprise Virtual Tape Library Market Share,

• #1 in Total Enterprise Tape Market Revenue, and • #2 in Tape Automation Market Share.1

1 Please see http://www.IDC.com for more information




IBM Virtualization Engine TS7700 The IBM TS7700 provides data accessibility, autonomic data management, massive scalability and ease of operations seldom found in other virtual tape solutions. Specifically, the TS7700 Grid architecture offers continuous multisite access to data required by today’s always-‐on 7x24x365 systems and applications. The tight connections between the TS7700 and z/OS also provide automated policy management for data within a TS7700 Cluster and/or across a grid. Further, the scalability offered by TS7700 in grid configurations can support the immense data repositories needed by current large-‐scale systems. At the same time, the TS7700 is well integrated into System z functionality, making virtual tape data operations intuitive and easy to use. Consequently, there is an emerging trend in some System z data centers to move more large data applications off of DASD and onto virtual tape to take advantage of its improved data availability, integrated data management and tremendous capacity.

In the pages that follow, we will discuss some of the more interesting characteristics of the TS7700 and its grid technology.2

TS7700 Grid access anywhere data TS7700 Grid technology represents a next step in the evolution of data access for IT systems. Essentially, the TS7700 Grid allows access to any virtual tape data from any device attached to a TS7700 Cluster joined to the grid. All nodes in the grid are equal entry points, and there is no concept of primary or secondary nodes. The virtual tape data could reside on a local or remote TS7700 and can be replicated. Regardless, what really matters is that System z has access to at least one online TS7700 Grid virtual tape device. The grid then takes care of the rest. The advanced data-‐at-‐a-‐distance technology of the TS7700 Grid provides unique capabilities that are not available from other virtual tape or DASD solutions.

For example, as shown in Figure 1 the zHost(s) in Chicago are accessing blue data located in the C cluster with data flowing through the B TS7700 into the host. In a like manner, the zHost(s) in New York are accessing green data located in the B cluster with the data flowing through the C TS7700 into the host. The A and D clusters are directly servicing data locally to their Chicago and New York host(s) respectively.

2 There are many more TS7700 capabilities and features available than can be covered in this short document. For more information on IBM TS7700 and TS7700 Grid functionality, please see http://www-‐03.ibm.com/systems/storage/tape/ts7700/.




As a result, virtual tape data doesn’t need to be hyper-‐swapped across locations with the TS7700 Grid. As long as other grid devices and data are online, hosts can access virtual tape data immediately from any grid location. Grid data just flows from one cluster across the network to another on demand as long as a host requires it.

Similarly, the moment a new TS7700 Cluster node has been added to a grid, it has immediate access to any data located across the connected TS7700s. So if data is being relocated across sites or a new data center location is being added to an IT environment, the new cluster node can have immediate access to all existing TS7700 Grid data.

Since the TS7700 is virtual tape data and its grid interconnect uses the IP protocol, it doesn’t have the severe distance limitations of FICON-‐attached DASD or FC-‐attached disk. Indeed, there are TS7700 Grids that span the Atlantic Ocean. Of course, data accessed across an ocean has longer response times, but this will not cause I/O failures because System z supports TS7700 devices as virtual tape with longer timeouts. Longer timeouts are not available when using DASD subsystems.

In addition, with Cluster Families of multiple TS7700s located in the same site and with multiple copies of data, a TS7700 Grid can provide automated load balancing. For local data, then, System z (z/OS), with input from the TS7700, will prefer devices in the most available cluster node and prefer data on disk to data that resides on physical tape. For remote data, then, z/OS, again with input from the TS7700, will take into consideration inter-‐cluster response times to determine which TS7700 virtual tape device to use to access data. Thus, z/OS customers can access grid data through the virtual tape device that supplies the best performance available, across the entire TS7700 Grid, at any instant in time.

Moreover, the TS7700 supports Selective Device Access Control to provide multi-‐tenancy, which allows exclusive host access to one or more volume ranges using separate tape management systems, independent volumes and scratch pools. In this fashion, a TS7700

Figure 1 TS7700 Grid data accessibility




Cluster can be hard-‐partitioned to support host logical partitions or segregated system complexes.

TS7700 Grid automated data replication Together, System z and the TS7700 Grid can manage replication of all data automatically. Using z/OS DFSMS Automatic Class Selection (ACS) routines and management class definitions, the TS7700 Grid can replicate data to clusters at virtual tape volume granularity. When a volume is created, ACS routines assign the virtual tape dataset to a management class and then z/OS transmits this class name to the TS7700. In the TS7700 Grid, this management class specifies how many copies to create, where those copies should exist and the replication method to be used for each independent copy. For instance, at dataset SYNC or tape end-‐of-‐volume, the TS7700 could automatically duplex the data to any peer node, then further replicate additional asynchronous copies to other nodes across the grid. Non-‐z/OS (System z) customers can also take advantage of TS7700 automated replication capabilities by assigning a management class policy to a range of volumes residing in the grid.

So, similar to cloud storage services of today,

• Any data deposited into a TS7700 Grid is automatically copied or duplexed to other cluster(s) as policy dictates,

• Any access to grid-‐replicated data is automatically serviced from the best possible

cluster accessible to a host, and • Any access to grid-‐replicated data is automatically rerouted around hardware

outages and retried against redundant instances in response to access failures.

All of the above require no operator intervention whatsoever and result in no data downtime.

As shown in Figure 2, the TS7700 Grid automatically replicates the green dataset to two other clusters and replicates the blue dataset to one other cluster, all while the hosts are accessing data. In this case, there’s triple redundancy for the green data and dual redundancy for the blue data. As the figure shows, both hosts are in an active-‐active configuration, creating and accessing data on all attached grid nodes. This TS7700 Grid is replicating data as a background activity in multiple directions both locally and remotely. There is no need for any node to be passive in this environment.




In contrast to most other data replication schemes that push data from a primary site to alternate site(s), the TS7700 grid uses pull replication. By means of pull replication, when a virtual tape reaches end-‐of-‐volume, other cluster nodes are notified and then can obtain the data from the source system or alternative source systems if other valid copies exist. When duplicating data to multiple TS7700s in a Cluster Family at the same site using TS7700 Cooperative Replication, only one copy of the data will be brought across and then other nodes can source their replica(s) locally rather than from the remote site, minimizing bandwidth consumption across distant links.

Furthermore, IBM was the first to deliver SYNC mode replication for System z virtual tape data with TS7700 Release 2.1 in December 2011. IBM’s TS7700 synchronous mode copy is at virtual tape sync point granularity. There is no dependency on Tape Management System pools or manual tape library definitions. As a result, each customer job can programmatically choose one replication method over another as well as dynamically adjust TS7700 replication activities to respond to environmental changes.

With TS7700 SYNC mode replication, volume content is duplexed to two nodes within a grid and volume data is “hardened” to persistent storage at any explicit or implicit sync point. Even before tape virtualization, applications have always made use of sync points to ensure data was physically present on tape. The TS7700 leverages these naturally occurring sync points in combination with parallel internal write buffers to keep two copies in step. Since TS7700 hardening occurs only at critical sync points, improved performance and much greater distance can be achieved over other solutions, which synchronize each virtual tape block. Given that System z applications view a data offload as valid only when sync commands complete successfully, the same level of zero recovery point objective can be achieved without the excessive hardening of each block written to virtual tape.

During the unlikely event of a hardware outage, the TS7700 Grid also tracks all changes that occur to any volume and reapplies updates automatically when the failing node comes back online. Hence, there is no need to failover or failback applications and data across sites. As such, recovery of a downed TS7700 node occurs automatically in the background when the cluster returns to operational status. With pull replication, the failed TS7700 can obtain

Figure 2 TS7700 automated data replication




data copies from wherever they currently reside, potentially using multiple clusters to reconstitute data.

Additionally, as soon as the TS7700 Cluster comes up, the previously failed system automatically understands the present status of all virtual tape volumes and provides instant access to all TS7700 Grid datasets, even if the data it has is no longer up to date. In this case, it retrieves replicated data from other locations while in the background simultaneously copying any data that needs to reside locally.

Similarly, if a disaster disables a whole data center, TS7700 clusters in other locations could automatically supply replicated volume data wherever needed. Presuming that the downed data center applications would now be running on hosts at an alternate site, all a customer would need to do is to vary online TS7700 Grid devices to the host(s) running those applications. In the same manner, customers could support four-‐site BC/DR configurations with the TS7700 Grid just as easily as the two-‐site solutions discussed above.

In a TS7700 Grid, new nodes can be added, and the grid can concurrently copy data automatically to the new node through the use of policy management software and IBM-‐provided tools. This process can be used to retire old hardware when sunsetting an existing datacenter or to add hardware when introducing a new datacenter. The new TS7700 Cluster can copy data either on demand or in the background depending on current host access requirements.

With TS7700 Grid policy-‐managed replication and access anywhere data availability, support for DR testing becomes almost a non-‐issue. The host(s) in the DR site can access any virtual tape data located across the grid but with appropriate DFSMS ACS routines, these hosts can create volumes in a management class isolated to local TS7700 Clusters. When DR testing completes, customers can delete those virtual tape volumes and return them to general scratch use or easily replicate select volumes back to the primary cluster.

TS7700 Grid massive scalability The TS7700 Virtualization Engine product family includes the TS7720 and the TS7740. Specifically,

• The TS7720 supports a disk-‐only configuration using large-‐capacity 3 TB NL-‐SAS disk drives with up to 624 TB of RAID6-‐protected usable capacity, and

• The TS7740 supports a 28 TB disk RAID6-‐protected cache using high-‐performance

600 GB SAS drives and attaches to a TS3500 tape library.

Both the TS7720 and TS7740 support disk drive, hardware-‐based, AES 128-‐bit, data-‐at-‐rest encryption with the use of internal key management. As a result, even if disk drives fall into the wrong hands, the information contained therein cannot be decrypted without its key.

IBM’s TS3500 tape library is a substantially scalable architecture—a single library can contain up to 192 tape drives and 20,000 physical tape cartridges. TS7740s connect to a TS3500 partition, which can contain up to 16 tape drives and 10,000 physical tape cartridges. Multiple TS7740 clusters can share a single TS3500, but each cluster must use a distinct partition.




The TS3500 normally supports TS1140 tape drives, but it can also attach to TS1130 and TS1120 tape transports. Each TS1140 tape drive can make use of multiple media types such as the

• IBM 3592 JC high-‐capacity cartridge with 4.0TB of native capacity, and

• IBM 3592 JK high-‐performance cartridge with up

to 500GB of capacity.

In addition, each TS1140 tape drive supplies up to 250 MB/second native data bandwidth or up to 650 MB/second of data bandwidth with hardware data compression. The TS1140 tape drive offers hardware, AES 256-‐bit, data-‐at-‐rest encryption that can take advantage of IBM Tivoli® Key Lifecycle Manager to generate and manage keys externally for added ease of use.

A TS7700 Grid that contains both TS7720 and TS7740 clusters forms a hybrid technology grid. In a hybrid-‐grid, customers can “pin” data to a disk-‐only TS7720 Cluster, or the data can reside there temporarily until it ages off and migrates to a TS7740.

As shown in Figure 3, data sent to the TS7720 can be in one of four states:

• Pinned Volumes, which will always remain on TS7720 disk for online access; • Prefer Remove Volumes, which will be migrated to TS7740s in least recently

accessed order in the event that the TS7720 runs out of disk space;

• Prefer Keep Volumes, which will be migrated to TS7740s in least recently accessed order in the event that the TS7720 runs out of disk space and there are no Prefer Remove candidates left; and

• Retained Volumes, which are temporarily pinned until a grace period passes, at

which time they will move to Prefer Keep or Prefer Remove status. As always, any migrated data can be accessed from any TS7700 Grid device wherever that data resides.




Moreover, in a hybrid-‐grid with both a TS7720 and a TS7740 in a Cluster Family at the same location, System z Scratch Allocation Assist can be used to direct workloads to specific clusters. Workloads that create primary data can be directed to TS7720 devices and backup/archive data can be directed to use TS7740 devices. Thus, when given the opportunity, z/OS can ensure that virtual tape data is written to the optimum node depending on application requirements.

Furthermore, TS7740 Copy Export functionality enables customers to export virtual tape data replicas out of a cluster through its TS3500 library. This exported data can then be imported into another TS7740 to transfer workloads across sites or support disaster recovery efforts.

Up to six TS7700 Cluster nodes can join in one grid located in a single data center across town or even across an ocean. With the latest release, any single standalone TS7700 or a TS7700 Grid now supports up to four million logical volumes that can be on tape, in disk cache or on disk storage for increased flexibility.

IBM designed the TS7720 and TS7740 systems from the ground up for enterprise reliability, availability and data integrity. As such, all TS7700s use System p® server hardware with IBM POWER7® for computing, AIX® for its OS and GPFS®/DB2® for data/metadata management inside the system.

IBM recently announced a Statement of Direction that the TS7700 will support deduplication services that should significantly reduce the capacity consumed by virtual tape data. Deduplication could potentially even reduce replication bandwidth consumption between sites. Thus, with deduplication, TS7700 can store even more data in the same physical space reducing total cost to store virtual tape data at the local and remote sites as well as be able to replicate data even faster than before.

Figure 3 TS7700 hybrid-‐grid functionality




TS7700 Grid z/OS integration The TS7700 Virtualization Engine is completely integrated into z/OS. This integration includes a proprietary TS7700 Perform Library Function Command interface and, as previously discussed, deep integration with DFSMS with no reliance on external tape management pools. Similarly, z/OS integration includes extensive support for device allocation preferencing when creating or accessing TS7700 Grid data.

Just as importantly, customers can use the z/OS operator console to monitor TS7700 Grid component status as well as modify many of its settings. An extensive web-‐based TS7700 operations GUI also provides configuration status, system performance and other information to aid in managing TS7700 Clusters and Grids. This GUI provides extensive historical information that shows how well the TS7700 is supplying host requests for data, migrating virtual tape data and replicating customer information across the grid.

Summary The TS7700 Grid provides access to data-‐at-‐a-‐distance and supplies near-‐instant data availability across sites, even sites that are continents away. In combination with z/OS policy management, the TS7700 offers fully automated data replication, which can support System z BC/DR capabilities that are easier to use as well as provide optimum data redundancy across TS7700 resources.

Even outside a grid configuration, the TS7740 offers the performance of disk data with the economics and immense capacity of physical tape libraries. Alternatively, the TS7720 can supply a sizeable disk-‐only configuration for those who need online access to data. Joining the two inside a hybrid-‐grid provides the advantages of both technologies through the automated device allocation available with z/OS and the TS7700 Grid-‐managed data migration.

In the end, the TS7700 Virtualization Engine extends many z/OS policy data management capabilities across a TS7700 Grid that System z customers have come to depend on for other types of data. All in all, the TS7700 offers an integrated, advanced technology solution to System z customers who need primary tape data and yet require continuous access to information from multiple data center sites across the globe.

Silverton Consulting, Inc., is a U.S.-based Storage, Strategy & Systems consulting firm offering products and services to the data storage community. QRcode: SilvertonConsulting.com Disclaimer: This document was developed with International Business Machines Corporation (IBM) funding. Although the document may utilize publicly available material from various sources, including IBM, it does not necessarily reflect the positions of such sources on the issues addressed in this document.

Silverton Consulting, Inc. StorInt™ Briefing - WordPress.com ·...

Documents

Transcript of Silverton Consulting, Inc. StorInt™ Briefing - WordPress.com ·...