408 Implementing the IBM Storwize V7000 with IBM Spectrum Virtualize V8.2.1
If you analyze the statistics and find that the system does not appear to be sending enough 
IOPS to your external SSD MDisk, you can always increase the load parameter.
Easy Tier operating modes
Easy Tier includes the following main operating modes: 
/SM590000Off
When off, no statistics are recorded and no cross-tier extent migration occurs. Also, with 
Easy Tier turned off, no storage pool balancing across MDisks in the same tier is 
performed, even in single tier pools
/SM590000Evaluation or measurement only
When in this mode, Easy Tier only collects usage statistics for each extent in a storage 
pool, if it is enabled on both the volume and the pool. No extents are moved. This 
collection is typically done for a single-tier pool that contains only HDDs so that the 
benefits of adding Flash drives to the pool can be evaluated before any major hardware 
acquisition.
/SM590000Automatic data placement/Storage pool balancing
In this mode, usage statistics are collected and extents. Extent migration is performed 
between tiers (if there is more than one pool in a tier). Also, auto-balance between MDisks 
of each tier is performed.
Implementation considerations
Consider the following implementation and operational rules when you use the IBM System 
Storage Easy Tier function on the Storwize V7000:
/SM590000Volumes that are added to storage pools use extents from the “middle” tier of three-tier 
model, if available. Easy Tier then collects usage statistics to determine which extents to 
move to “faster” T0 or “slower” T2 tiers. If there are no free extents in T1, extents from the 
other tiers are used.
/SM590000When an MDisk with allocated extents is deleted from a storage pool, extents in use are 
migrated to MDisks in the same tier as the MDisk that is being removed, if possible. If 
insufficient extents exist in that tier, extents from the other tier are used.
/SM590000Easy Tier monitors extent I/O activity of each copy of a mirrored volume. Easy Tier works 
with each copy independently of the other copy. 
/SM590000For compressed volumes on standard pools, only reads are analyzed by Easy Tier.
/SM590000Easy Tier automatic data placement is not supported on image mode or sequential 
volumes. However, it supports evaluation mode for such volumes. I/O monitoring is 
supported and statistics are accumulated.
Note: The auto-balance process automatically balances existing data when MDisks are 
added into a pool. However, it does not migrate extents from existing MDisks to achieve 
even extent distribution among all old and new MDisks in the storage pool. The Easy 
Tier migration plan is based on performance. It is not based on the capacity of the 
underlying MDisks or on the number of extents on them.
Note: Volume mirroring can have different workload characteristics on each copy of the 
data because reads are normally directed to the primary copy and writes occur to both 
copies. Therefore, the number of extents that Easy Tier migrates between the tiers 
might differ for each copy.