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EVA3000 with mixed drive types

Ph. Leenman
Occasional Contributor

EVA3000 with mixed drive types


Case: EVA3000 historical configuration with a number of 72 GB disks and a number of 300GB add-on disks in the default DG.
With Command View I can check the default DG.
I have a raw capacity for this DG of appr. 1900GB and a total storage space of ~1250GB (net available). The storage space used is appr. 550GB, so actual available space is ~700GB.
The disk group properties say:
Occupancy: 550GB, failure prot. single
This is clear and looks OK for sparing level setting etc.

Strange thing is the following:
In the diskgroup properties there is also:
Total capacity: 1241GB
Vraid0 362GB
Vraid1 181GB
Vraid5 182GB

When creating a new vdisk I cannot go greater than this 362GB for a Vraid0 disk while ~700GB is available.
Can anyone explain this? Is this because there is a mix of two types of disks in this DG?



Hein van den Heuvel
Honored Contributor

Re: EVA3000 with mixed drive types

You may want to create an official support case for this. The numbers sound a little out of whack. The system is not still actively rebalancing/leveling (or some such)? Gave it enough time to settle?

Just today someone posted an Eva best practices document in the hpux forum: http://forums1.itrc.hp.com/service/forums/questionanswer.do?threadId=850958

> Is this because there is a mix of two types of disks in this DG?

The document attached to the above suggest that the Eva nicely incorporates all the space. I quote:
"The EVA will attempt to ensure that the amount on each physical disk drive is proportional to that driveâ s contribution to the overall capacity. This means that larger drives will have more data on them than smaller drives. As an example, a 72 GB disk will have twice as much user data on it as a 36 GB drive. In a random access type of application, this implies that the larger drives will have twice as much I/O as the smaller drives, resulting in an I/O load imbalance at the disk drive level."

Hope this helps a little....