Vmware Vstorage Api For Array Integration Support - IBM DS8900F Introduction And Planning Manual

Table 16. Drive class combinations and tiers for systems with Flash Tier 1 drives as the highest performance
drive class
Drive classes
Flash Tier 1
Flash Tier 2
Cold demotion
Cold data (or extents) stored on a higher-performance tier is demoted to a more appropriate tier. Easy
Tier is available with two-tier disk-drive pools and three-tier pools. Sequential bandwidth is moved to
the lower tier to increase the efficient use of your tiers.
Warm demotion
Active data that has larger bandwidth is demoted to the next lowest tier. Warm demotion is triggered
whenever the higher tier is over its bandwidth capacity. Selected warm extents are demoted to allow
the higher tier to operate at its optimal load. Warm demotes do not follow a predetermined schedule.
Warm promotion
Active data that has higher IOPS is promoted to the next highest tier. Warm promotion is triggered
whenever the lower tier is over its IOPS capacity. Selected warm extents are promoted to allow the
lower tier to operate at its optimal load. Warm promotes do not follow a predetermined schedule.
Manual volume or pool rebalance
Volume rebalancing relocates the smallest number of extents of a volume and restripes those extents
on all available ranks of the extent pool.
Auto-rebalancing
Automatically balances the workload of the same storage tier within both the homogeneous and the
hybrid pool that is based on usage to improve system performance and resource use. Use the auto-
rebalancing functions of Easy Tier to manage a combination of homogeneous and hybrid pools,
including relocating hot spots on ranks. With homogeneous pools, systems with only one tier can use
Easy Tier technology to optimize their RAID array usage.
Rank depopulations
Allows ranks that have extents (data) allocated to them to be unassigned from an extent pool by using
extent migration to move extents from the specified ranks to other ranks within the pool.
Easy Tier provides a performance monitoring capability, regardless of whether the Easy Tier feature is
activated. Easy Tier uses the monitoring process to determine what data to move and when to move it
when you use automatic mode. You can enable monitoring independently (with or without the Easy Tier
feature activated) for information about the behavior and benefits that can be expected if automatic mode
were enabled.
Data from the monitoring process is included in a summary report that you can download to your local
system.

VMware vStorage API for Array Integration support

The storage system provides support for the VMware vStorage API for Array Integration (VAAI).
The VAAI API offloads storage processing functions from the server to the storage system, reducing the
workload on the host server hardware for improved performance on both the network and host servers.
The following operations are supported:
Atomic test and set or VMware hardware-assisted locking
The hardware-assisted locking feature uses the VMware Compare and Write command for reading
and writing the volume's metadata within a single operation. With the Compare and Write command,
the storage system provides a faster mechanism that is displayed to the volume as an atomic action
that does not require locking the entire volume.
40 IBM DS8900F: DS8900F Introduction and Planning Guide
Drive class combinations
Flash Tier 1
0
Flash Tier 1 + Flash Tier 2
0
1