Advanced Storage Concepts
Upon completion of this module, you should be able to:
• Describe LUN Migration
• Describe FAST VP
• Describe FAST Cache
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Advanced Storage Concepts
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Advanced Storage Concepts
Lesson 1: LUN Migration and LUN Expansion
During this lesson the following topics are covered:
• Benefits of LUN migration
• Migrating a LUN
• Pools LUNs expansion procedures
• Classic LUNs expansion (MetaLUN) concept
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Advanced Storage Concepts
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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
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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
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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
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Starting a LUN Migration: Source LUN
Storage > Storage Configuration > Storage Pools
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Starting a LUN Migration: Destination LUN
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Viewing LUN Migration State
Storage > Storage Configuration > Storage Pools
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LUN Migration Completion
Storage > Storage Configuration > Storage Pools
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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
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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
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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
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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
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Classic LUNs expansion (MetaLUN) Wizard
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Pool LUN Expansion: Host (Part 1)
1
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2
Advanced Storage Concepts
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Pool LUN Expansion: Host (Part 2)
3
4
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Advanced Storage Concepts
Lesson 1: Summary
During this lesson the following topics were covered:
• Benefits of LUN migration
• Migrating a LUN
• Pools LUNs expansion procedures
• Classic LUNs expansion (MetaLUN) concept
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Advanced Storage Concepts
Lesson 2: FAST VP
During this lesson the following topics are covered:
• FAST VP functionality
• Benefits of FAST VP
• Configuring a heterogeneous Pool
• Configuring FAST VP
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FAST VP Functionality
• Software that automates
Pool
BEFORE
movement of data based on level
of activity
 More active data on faster
Flash
drives
LUN 1
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
AFTER
SAS
drives
LUN 2
NL-SAS
drives
Most active data
Moderately active data
Least active data
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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
•
Data Optimization
FLASH
SAS
New
FLASH
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NL-SAS
Rebalancing
fairly stable over time
VNX provides a unified approach to auto-tiering for file and block
Pool
data
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Heterogeneous Pools
Drives
Flash
NL-SAS
SAS
Storage Tiers
Flash
SAS
NL-SAS
Storage
Flash - Extreme Performance
SAS - Performance
Pool
NL-SAS - Capacity
Most active data
Moderately active data
LUNs
Least active data
Optimized auto-Tiering
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Per-Tier RAID Configuration
RAID 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
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Storage Tiers
Tier
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
AUTOMATIC DATA OPTIMIZATION
Flash
SAS
NL-SAS
(Extreme
(Performance) (Capacity)
performance
)
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Creating a Heterogeneous Pool
Storage > Storage Configuration > Storage Pools
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Configuring a Heterogeneous Pool
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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
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Managing and Monitoring FAST VP
Storage Pool Properties
Use the dropdown to display
additional options such as
Manual
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Managing Auto-Tiering with Unisphere
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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
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Starting and Stopping Data Relocation
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Unisphere Tiering Summary
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Advanced Storage Concepts
Lesson 2: Summary
During this lesson the following topics were covered:
• FAST VP functionality
• Benefits of FAST VP
• Configuring a heterogeneous Pool
• Configuring FAST VP
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Advanced Storage Concepts
Lesson 3: FAST Cache
During this lesson the following topics are covered:
• FAST Cache functionality
• Benefits of using FAST Cache
• Configuring FAST Cache
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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
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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
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VNX FAST Cache Components
• Policy Engine
Host I/O
 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
Multicore
Cache
(De-stage &
Read Miss I/O)
Memory Map
• 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
SSD
(Hit)
Multicore
FAST
Cache
SSD
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HDD
(Miss)
HDD
SSD
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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
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Configuring VNX FAST Cache
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Creating FAST Cache
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Enabling FAST Cache
Classic LUN creation
Pool creation
Classic LUN Properties
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Pool Properties
Advanced Storage Concepts
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FAST Cache Column: Unisphere
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FAST Cache CLI Commands
Task
NaviSecCli command
Create FAST Cache
cache –fast –create
Destroy FAST Cache
cache –fast –destroy
Get 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 chglun -<LUN#> -fastcache 0 I 1
a Classic LUN
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
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FAST Cache Configuration Options
Storage System
Flash (SSD) Disk
Capacity
Maximum FAST Cache
Capacity
VNX5400
100 GB / 200 GB
0.5 TB / 1 TB
VNX5600
100 GB / 200 GB
1 TB / 2 TB
VNX5800
100 GB / 200 GB
1.5 TB / 3 TB
VNX7600
100 GB / 200 GB
2.1 TB / 4.2 TB
VNX8000
100 GB / 200 GB
2.1 TB / 4.2 TB
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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
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Advanced Storage Concepts
Lesson 3: Summary
During this lesson the following topics were covered:
• FAST Cache functionality
• Benefits of using FAST Cache
• Configuring FAST Cache
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Summary
Key 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.
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