Advanced Storage Concepts

Copyright © 2014 EMC Corporation. All Rights Reserved.

Advanced Storage Concepts

Upon completion of this module, you should be able to:• Describe LUN Migration• Describe FAST VP• Describe FAST Cache

Advanced Storage Concepts 1



During this lesson the following topics are covered: • Benefits of LUN migration• Migrating a LUN• Pools LUNs expansion procedures• Classic LUNs expansion (MetaLUN) concept

Lesson 1: LUN Migration and LUN Expansion



LUN Migration Benefits• Storage system tuning feature used to change:

LUN’s type LUN’s storage pool topology Location within the storage system LUN’s capacity

• No disruption to applications running on the host• Can enhance performance or increase disk utilization• Thin LUN space reclamation via LUN Migration

Move from a Classic LUN or a Thick LUN



LUN Migration Restrictions• Neither LUN may be a private LUN• Neither LUN may be binding, expanding, or migrating• Either or both may be metaLUNs• Destination LUN may not be in a Storage Group• Destination LUN may not be part of SnapView or MirrorView

operations• Destination LUN may be larger than Source LUN



LUN Migration Operation• Data is copied from Source LUN to Destination LUN

Source stays online and accepts I/O• Destination assumes identity of Source when copy completes

LUN ID, WWN storage group membership

• Source LUN is unbound after copy completes• The migration process is non-disruptive

There may be a performance impact• LUN Migration may be cancelled at any point

Source LUN returns to its previous state Destination LUN is destroyed



Starting a LUN Migration: Source LUNStorage > Storage Configuration > Storage Pools



Starting a LUN Migration: Destination LUN



Viewing LUN Migration StateStorage > Storage Configuration > Storage Pools



LUN Migration CompletionStorage > Storage Configuration > Storage Pools



LUN Migration Considerations• Ensure FAST Cache is OFF on LUNs being migrated

Prevents the migration’s I/O from consuming capacity in the FAST Cache

• LUN migrations into FAST VP pool-based LUNs Tiering policy determines which tier will be first allocated to

• LUN migrations with virtual provisioning pool thin LUNs Lower rate of migration when thin LUN is involved Depends on thin LUN is populated and how sequential the data is

• Use ASAP priority LUN migration with normal cache settings with caution



Pool LUN Expansion• Capacity immediately available• Thick LUN

Pool must have enough storage for the expansion to succeed• Thin LUN

Storage does not need to be available



Classic LUNs Expansion (MetaLUN) Concepts• Aggregation of multiple LUNs to make a new storage object

Aggregation via striping or concatenation MetaLUN preserves personality of base LUN

• Striping can preserve performance profile of base LUN Same RAID type and LUN size must be used Restriping data from a populated base LUN takes time

• Concatenation is immediate Performance profile of components may vary RAID type and LUN size do not have to be the same

• Volume Managers and concurrency Volume Managers can increase concurrency to the storage system No multi-threading with a metaLUN



Classic LUNs Expansion (MetaLUN) Guidelines• Concatenation – immediate

No performance impact because no data must be moved or copied

• Striped metaLUN built from scratch – immediate Create a new base LUN, then expand it No performance impact; VNX Block OE is aware that no data needs to move

• Stripe expanding a populated Base LUN - time depends on size of Base LUN All Base LUN data is read and restriped even if only one block was written

• Expand a LUN while app is running – time depends on size and workload All data must be read and striped Host workload and metaLUN expansion operations share storage system resources

• Re-stripe time is independent of element size multiplier• Expanding more than one LUN at a time per RAID Group is not recommended



Classic LUNs expansion (MetaLUN) Wizard



Pool LUN Expansion: Host (Part 1)


1 2


Pool LUN Expansion: Host (Part 2)


4

3



During this lesson the following topics were covered:• Benefits of LUN migration• Migrating a LUN• Pools LUNs expansion procedures• Classic LUNs expansion (MetaLUN) concept

Lesson 1: Summary




During this lesson the following topics are covered: • FAST VP functionality• Benefits of FAST VP• Configuring a heterogeneous Pool• Configuring FAST VP

Lesson 2: FAST VP



FAST VP Functionality• Software that automates

movement of data based on level of activity More active data on faster

drives, less active data on slower drives

• Less active data can usually be moved from Tier 1 storage without users noticing the difference

• Uses I/O statistics at a 256 MB slice granularity


LUN 2

LUN 1

PoolBEFORE AFTER

Most active dataModerately active data

Least active data

Flashdrives

SASdrives

NL-SASdrives


Benefits of FAST VP• Eliminates the need to manually migrate LUNs between pools

Automatic data relocation within a tier• Rebalances data when drives are added to a Pool• Optimizes the use of high performance and high capacity drives• Improves performance and cost efficiency• Recommended for applications that have workloads that are

fairly stable over time• VNX provides a unified approach to auto-tiering for file and block

data


Pool

New FLASH

NL-SASSASFLASH

Data Optimization

Rebalancing

Rebalancing


Heterogeneous Pools


Drives

LUNs

Storage

Optimized auto-Tiering

NL-SAS

Flash SAS NL-SAS

Pool

Most active dataModerately active data

Least active data

Flash - Extreme Performance

SASFlash

SAS - Performance

NL-SAS - Capacity

Storage Tiers


Per-Tier RAID ConfigurationRAID Type Preferred Drive

Count Options

RAID 1/0 4+4

RAID 5 4+1, 8+1

RAID 6 6+2, 14+2


• Only one RAID type per tier• Mix and match in Pool, e.g.

RAID 5 (4+1) for Flash RAID 5 (8+1) for SAS RAID 6 (14+2) for NL-SAS


Storage TiersTier Drive Technology Criteria for Storage

Extreme Performance Flash (SSD) • Response times• Performance

Performance Serial Attach SCSI (SAS)

• Performance and Capacity

Capacity Near-Line SAS (NL-SAS)

• Maximum capacity at a modest performance level


NL-SAS(Capacity)

SAS(Performance)

Flash (Extreme

performance)

AUTOMATIC DATA OPTIMIZATION


Creating a Heterogeneous PoolStorage > Storage Configuration > Storage Pools



Configuring a Heterogeneous Pool



FAST VP Policies• Start High, then Auto-Tier

Data initially placed in highest tier, then allowed to relocate• Auto-Tier

Moves data to a tier based on LUN performance statistics• Highest Available Tier

Moves data to the highest tier available • Lowest Available Tier

Moves data to the lowest tier available• No Data Movement

Moves no data between tiers, and retains the current tier placement



Managing and Monitoring FAST VP


Use the dropdown to display additional options such as Manual

Storage Pool Properties


Managing Auto-Tiering with Unisphere


Copyright © 2014 EMC Corporation. All Rights Reserved. Advanced Storage Concepts 29

Starting and Stopping Data Relocation• Array-wide Relocation Schedule allows the user to define the

days and duration for relocations• Each pool has the option of using the array-wide scheduler:

For existing Pools, when FAST VP is installed, the default setting is OFF

For Pools created after FAST VP is installed, the default setting is ON

• Users can over-ride the setting as needed• All Pools have a manual “relocate now” option


Starting and Stopping Data Relocation



Unisphere Tiering Summary




During this lesson the following topics were covered:• FAST VP functionality• Benefits of FAST VP• Configuring a heterogeneous Pool• Configuring FAST VP

Lesson 2: Summary




During this lesson the following topics are covered: • FAST Cache functionality• Benefits of using FAST Cache• Configuring FAST Cache

Lesson 3: FAST Cache



VNX FAST Cache Definition and Functionality• Storage system-based licensed software

Uses Enabler• FAST Cache extends storage system cache capacity

Adds a second cache tier Promotes frequently accessed data to Flash drives

• FAST Cache acts as an application accelerator • FAST Cache operations are non-disruptive

Uses existing memory allocation interface and does not use host cycles

• Can be enabled on Classic LUNs and Pools



Benefits of VNX FAST Cache• Leverages the lower response time and better IOPS of Flash

drives Without dedicating Flash drives to specific applications Provides Flash drive level performance to the data which is

accessed most frequently • Reduces the load on other storage system resources• Improves Total Cost of Ownership (TCO) of the system• Works in a complementary way with FAST VP technology



VNX FAST Cache Components• Policy Engine

Manages the flow of I/O through FAST Cache

Decides when I/O should be copied to HDD and vise versa

Maintains statistical information about the data access patterns

• Memory Map Tracks extent usage and ownership in

64 KB chuncks of granularity Maintains information on the state of

64 KB chunks of storage and the content

A copy is stored in DRAM memory


Host I/O

MulticoreCache

Multicore FAST Cache

SSD SSD

HDD

(De-stage &Read Miss I/O)

Memory Map

SSD(Hit)

HDD(Miss)


VNX FAST Cache Operations• Host read/write operation

Flash drives are configured as RAID 1 mirror pairs Application gets the acknowledgement for an IO operation

• FAST Cache promotion Data is copied from spinning media HDDs and placed into FAST Cache

• FAST Cache flush A FAST Cache page is copied to the HDDs and the page is freed for use

• FAST Cache cleaning Process that proactively copies dirty pages to the underlying physical

devices



Configuring VNX FAST Cache



Creating FAST Cache



Enabling FAST Cache

Classic LUN creation

Classic LUN Properties

Pool creation

Pool Properties



FAST Cache Column: Unisphere

41Advanced Storage Concepts


FAST Cache CLI Commands

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Task NaviSecCli commandCreate FAST Cache cache –fast –createDestroy FAST Cache cache –fast –destroyGet FAST Cache info cache –fast -info Configure FAST Cache when creating a Classic LUN

bind ... –fastcache 0 I 1

Enable or disable FAST Cache on a Classic LUN

chglun -<LUN#> -fastcache 0 I 1

Get FAST Cache config info on a Classic LUN

getlun <LUN#> -fastcache

Configure FAST Cache when creating a storage pool

storagepool –create ... –fastcache on I off

Configure FAST Cache on existing storage pool

storagepool –modify –id <#> -fastcache on I off

Get FAST Cache state on storage pool

storagepool –list –id <#> -fastcache



FAST Cache Configuration Options

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Storage System Flash (SSD) Disk Capacity

Maximum FAST Cache Capacity

VNX5400 100 GB / 200 GB 0.5 TB / 1 TBVNX5600 100 GB / 200 GB 1 TB / 2 TBVNX5800 100 GB / 200 GB 1.5 TB / 3 TBVNX7600 100 GB / 200 GB 2.1 TB / 4.2 TBVNX8000 100 GB / 200 GB 2.1 TB / 4.2 TB



VNX FAST Cache Summary• FAST Cache enables the system cache to be expanded by using

Flash drives as an additional tier of cache Allows the storage system to provide Flash drive performance to

the most heavily accessed chunks of data • FAST Cache absorbs I/O bursts from applications

Reduces the load on backend hard disks Improves the TCO of the storage solution

• FAST Cache works in a complementary way with FAST VP technology Both technologies help in placing data segments on the most

appropriate storage tier based on their usage pattern




During this lesson the following topics were covered:• FAST Cache functionality• Benefits of using FAST Cache• Configuring FAST Cache

Lesson 3: Summary



SummaryKey points covered in this module:• LUN migration restrictions include: No private, binding,

expanding, or migrating LUNs; Destination not in a Storage Group or part of SnapView/MirrorView operation

• FAST VP feature automatically migrates the data between storage tiers, and within storage tiers, providing lowest TCO.

• FAST Cache uses Flash drives and helps with read and write performance for frequently accessed data when this feature is enabled for or LUNs.


Advanced Storage Concepts

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