Creating an Easy Tier (aka Multi-tier) pool within IBM’s Storwize is pretty simple, just it cannot be done via its GUI. The GUI definitely lacks this functionality, and thus I had to resort to learning some IBM CLI for the Storwize(V5000). I have been told (from IBM) the command(s) are the same for both the Storwize v7000 and v3700 series as well.
The benefits of IBM’s Easy Tier is rather impressive, and I am sure (please correct me if I am wrong) this exists within other SAN vendors as well. In my pool, there are three types of disk drives, SSD and SAS (both enterprise grade and nearline). The benefits of the multi-tiered (easy tier) pool allows data to be (seamlessly) migrated to higher-IO drives/pools that provide higher performance, ie. SSD pools.
In my case this is great, as I will have heavy-hitting IOPS SQL virtual machines that will probably require the higher performing SAS if not SSD drives. And whereas low-IOPS hitting data such as Quorums on nearline drives.
As IBM states, “Easy Tier can automatically migrate data at the sub-LUN/sub-volume level to the most appropriate storage tier. This includes the ability to automatically and non-disruptively relocate logical volume extents with high activity to storage media with higher performance characteristics, while extents with low activity are migrated to storage media with lower performance characteristics.”
So how is this all done?
I am going to assume you have already created your mdisk/RAID groups. In my case my SSD drives are a RAID-5 likewise with my SAS (enterprise) drives. RAID-6 for my SAS nearline drives.
Within the CLI, you will need to get the IDs of all your drives, you can do this by running the following command, “lsdrive“. Now you can see all your drives, and their disk types, IDs, etc.
Now you need to create your Easy Tier pool with the mkarray command. (More syntax info can be found HERE)
“mkarray -level <raidType> -drive <IDrangeOfDrivesPerDiskTypeGroupSepeartedByColon(s)> <YourPoolName>”
“mkarray -level raid5 -drive 0:1:2:3 EasyTier-Pool“
*Do not forget to leave 1 drive behind as a spare within your MDisk pool, otherwise you will have no hot-spare, and will have to rebuild*
Once you have created your pool, and assoicated all the drives to the Easy Tier pool, you can now see all the mdiskX groups, using the lsmdisk command.
For more details, use the lsmdiskgrp command.
We can now also confirm the Easy Tier pool within the GUI.
Now we can start building/migrating or whatever it is your SAN was designed for! 🙂
For more literature on IBM’s Easy Tier, please visit the LINK.