Legacy HDS Forums

HUS and Dynamic Tiering

Discussion created by Legacy HDS Forums on Dec 10, 2012
Latest reply on Dec 11, 2012 by Legacy HDS Forums

Originally posted by: paulmsteel


First time I have configured the Dynamic Tiering (HDT) feature on a HUS (HUS110 actually) and I wanted to share a couple of bits that aren't really clear:

First make sure you have at a minimum SNM 2 v23.00 and array firmware 0930/A
Install the Dynamic Provisioning (prerequisite software feature for HDT) and Dynamic Tiering licenses as you normally would
on the array

This will enable the "Change Tier Mode" button in SNM 2 the DP Pools pane

Add the licensing first, then create the DP Pool with Tier Mode enabled (note selct the Tier Mode enable button first because if you have added Raid Groups first it will refresh the screen to blank again)
Now in creating the HDT DP Pool for the first time select your underlying Raid Groups and add them all:
For example:
SSD 3+1 by 1
SAS 4+1 by 4
NL-SAS 8+2 by 4
This will add the underlying Raid Groups into the DP Pool and it will now be displayed as "Mixed"
It will also add the Raid Groups in nice sequential numbers (us storage guys being a bit OCD)

With Tier Mode is enabled and when you select SSD disk and do not select an even multiple (2, 4, 8 and 16) of data disks, DP
efficiency will be reduced
I had an issue with a pre-existing (pre HDT license installed) DP Pool containing SSD disks - the issue was that the Tier Mode could not be changed with an error: "DMED260063: The process cannot be performed because the specified DP Pool consists of SSD"
To fix it I had to delete the DP Pool containing the SSD disks and recreate it post HDT license install.

Also get your hands on the "Hitachi Unified Storage Provisioning Configuration Guide" MK-91DF8277-02 from HDS.