Title: Easy Tier benefits extend beyond just having SSDs
Easy Tier is a DS8000 built-in dynamic data relocation feature that allows host transparent movement of data among the storage system resources. This significantly improves configuration flexibility as well as performance tuning and planning.
There appears to be a misconception by many that to derive benefit from the Easy Tier feature on a DS8700/DS8800, you have to also include SSDs. This is not accurate as Easy Tier provides significant benefit without the inclusion of SSDs. The following information pertains to DS8700s and DS8800s with a microcode level of R5.1 and R6.1 or higher.
The first thing to be aware of is that even without the Easy Tier feature installed, the DS8700 and DS8800 enables workload statistical data collection. These statistics are used by the Easy Tier Automatic Mode facility to identify data that might benefit most from relocation to higher performing storage. The statistical data can be downloaded and further processed with the Storage Tier Advisor Tool (STAT). The tool provides recommended SSD capacity required and predicted performance improvement and also
a graphical representation of hot data distribution at the volume level. This allows an analysis of the workload characteristics and gives you a clear understanding of what application data can benefit the most from relocation to SSDs, Enterprise (SAS/FC) drives or Nearline SATA drives.
With the no charge Easy Tier feature installed on the DS8700 or DS8800, even without SSDs, the new functions included in Easy Tier provide significant new capabilities that users have not previously enjoyed with the DS8000.
Easy Tier can be used in either manual or automatic mode.
- Easy Tier Manual Mode:
Easy Tier Manual Mode allows a set of manually initiated actions to relocate data among
the storage system resources in a dynamic fashion; that is, without any disruption of the
host operations. The Manual Mode capabilities include dynamic volume relocation,
dynamic extent pool merge, and rank depopulation.
Dynamic volume relocation allows a DS8000 volume to be migrated to the same or another extent pool. This capability also provides the means to rebalance extents across the pool when additional capacity is added to a pool. Dynamic extent pool merge allows an extent pool to be merged to another extent pool.
Rank depopulation allows the relocation of in-use extents from one
rank to the other ranks in the same extent pool. The purpose of this is to allow a rank to be unassigned from the extent pool.
None of the above functions require SSDs to be installed. For clients requiring FDE drives, manual mode is fully supported.
- Easy Tier Automatic Mode:
In Automatic Mode, Easy Tier can autonomically manage the capacity allocated in an
extent pool containing a mix of two disk technologies (or tiers) in order to place the most
demanding data (hot data) on the appropriate storage. Extents can be migrated between any two tiers. One of the tiers does NOT have to be SSDs.
On the DS8700, the supported tiers are Solid State Drives (SSDs) and FC Enterprise Disk; SSD and Nearline Disk (Serial Advanced Technology Attachment or SATA) or FC Enterprise Disk and Nearline Disk.
The DS8800 supports SSDs and SAS Enterprise Disk tiers.
In Automatic Mode, Easy Tier also provides an auto-rebalance capability to continuously provide good performance by balancing the load on the ranks and on disk Device Adapters pairs. Currently this is supported in hybrid pools. When a rank has a high utilization and other ranks have low utilization, Easy Tier will relocate extents from the busy rank to another rank of the same tier.
One should also remember that Easy Tier enhancements are continually being developed and will become even better in the future.
For more information on Easy Tier, please go these web sites:
IBM® System Storage™ DS8700™ and DS8800™ Performance with Easy Tier® 2nd Generation
http://w3-03.ibm.com/support/techdocs/atsmastr.nsf/WebIndex/WP101961
IBM System Storage DS8000 Easy Tier
http://www.redbooks.ibm.com/abstracts/redp4667.html
Easy Tier Deep Dive - Part 1 - DS8000
http://w3-03.ibm.com/support/techdocs/atsmastr.nsf/WebIndex/PRS4659
http://partners.boulder.ibm.com/src/atsmastr.nsf/WebIndex/PRS4659
Accelerate with ATS: Easy Tier Webinar
http://w3-03.ibm.com/support/techdocs/atsmastr.nsf/WebIndex/PRS4049
© Copyright 2011, IBM Corporation Version 8/16/2011
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