Virtual Provisioning, Storage Pools and FLARE 30

23 08 2010

A while back I wrote about best practices for CLARiiON and Virtual Provisioning, and while it was an excellent feature when introduced with FLARE 28.5,..it’s gotten even better in FLARE 30.

If your not versed on the concept of Storage Pools yet then search through www.varrowblogs.com as there is a ton of good info on the subject, but the important thing to know if that prior to FLARE 30 the recommendation of EMC was to use Homogeneous pools only.  This basically means storage pools that are comprised of a single drive type.  FLARE 28.5 allowed the use of either Fibre Channel or SATA drives in a single pool, and FLARE 28.7 added EFDs to the list.

With the release of FLARE 30, the types of storage pools were extended to include Heterogeneous pools which enable multiple drive types, FC, SATA and EFD,  to be included in a single pool.  Heterogeneous pools are the essential foundation of FAST, or Fully Automated Storage Tiering, i.e. the ability for the storage array to make autonomous decisions on where to best place storage based upon performance requirements, and offer the most flexibility when allocating storage via the pool format.

When putting any new technology or feature to use, it’s always important to know all of the caveats.  Listed below is a brief summary of the best practices in conjunction with Storage pools and Virtual Provisioning, specifically in scope of FLARE 30:

  • Storage pools can be configured as RAID 5, RAID 6, or RAID 1/0
  • Homogeneous pools are still recommended for applications with similar performance requirements, and/or when you don’t plan to leverage FAST
  • Heterogeneous and Homogeneous pools both support a single RAID type
  • There can be a maximum of 3 tiers in a Heterogeneous pool, based on 3 drive types, but FAST storage pools can be comprised of a minimum of 2 drive types
  • RAID 5 pools are recommended for the majority of workloads
  • As of FLARE 30, a storage pool can be as large as the maximum number of drive in a given array model, less the vault drives and hot spares
  • Storage pools are recommended to be built in multiples of 5 for RAID 5, multiples of 8 for RAID 6, and multiples of 8 for RAID 1/0.  Very large pools should be allocated using RAID 6 but ultimately your requirements should be validated to ensure the best mix of performance and resource utilization
  • If creating a pool using differing drive types, create the initial pool using 1 drive type only, and then expand the pool in stages using the remaining drive types, grouped by specific drive type for each expansion stage
  • Thick LUNs, introduced in FLARE 30, reserve all space in a storage pool corresponding to the LUN size when created, and in general perform better than Thin LUNs
  • The maximum size for a storage pool-based LUN is 14TB
  • FLARE 30 introduced the ability to dynamically expand and shrink pool LUNs which is a vary easy process compared to dealing with metaLUNs, however, LUNs can only be shrunk when used in conjunction with Windows 2008
  • EMC recommends that the default owner of a pool LUN not be changed once it is provisioned as it can impact performance
  • Space reclamation was introduced with FLARE 30 and allows allocated space not in use to be freed up from a LUN.  This process can be initiated either through performing a LUN migration or by migrating via SAN Copy
  • SnapView supports both thin and think LUNs (thick LUN support was introduced with FLARE 30)
  • A minimum of FLARE 29 must be in use on both source and destination arrays for replication of thin LUNs.  Thick LUNs can be migrated only if the source array is running FLARE 30.  The same holds true for SAN Copy
  • RecoverPoint supports CDP and CRR for thin, thick, and of course traditional LUNs

Reference the following white paper for additional information:

https://powerlink.emc.com/nsepn/webapps/btg548664833igtcuup4826/km/live1/en_US/Offering_Technical/White_Paper/H5512-emc-clariion-virtual-provisioning-wp.pdf?mtcs=ZXZlbnRUeXBlPUttQ2xpY2tTZWFyY2hSZXN1bHRzRXZlbnQsZG9jdW1lbnRJZD0wOTAxNDA2NjgwNTIzOTAzLGRhdGFTb3VyY2U9RENUTV9lbl9VU18w

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28 08 2010
Technology Short Take #2 - blog.scottlowe.org - The weblog of an IT pro specializing in virtualization, storage, and servers

[…] Matt Hensley recently did a write-up on some of the new functionality in this post on virtual provisioning, storage pools, and FLARE 30. It’s worth a read if you aren’t already familiar with these technologies and need a […]

17 02 2011
Celerra DART 6.0.x with Clariion FLARE 30 GOTCHA « GOING VIRTUAL

[…] One of the biggest changes in Flare 30 was the introduction of storage Pools which is quite different to the traditional “Raid Group” concept which has been around for donkeys years. If you want to read a bit more in depth information about Storage Pools, then check out Matt Hensleys post here. […]

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