How long to add new disks in VA7410?

[Jack Fan]

Hi All,

Are there any way to estimate this duration needed to install new chassis and new disks in VA7410 server? once new disks installed on VA7410 then disk array automatic perform disk block balancing, and if it impact existing production system which connecting on VA7410? cause heavy loading or NOT?

Can I have a formula for estimation?

My VA7410...

two chassis/enclosure,
15*36GB(15000rpm) installed in chassis #1.
8*36GB (15000rpm) installed in chassis #2.

22 LUN created in VA7410....15GB for each one...

Thank in advance...

Jack Fan

[David Child_1]

Jack,

I don't know if there is anyway to predict how much of an impact this will have. The same applies to the time it will take. From what I understand the array will try to optimize/balance when it has free cycles. If your array is being heavily utilized then it could take a very long time to complete the balancing.

David

[Tim D Fulford]

Jack.

I dont have n exact answer for you. It is obviously dependant on how big and fast the disks are.

We had a VA7400 with 30x 73GB disks (10,000) already configured. We added an extra 30x 18GB disks (15,000 rpm) and saw performance degradation some 4 hours after they were added. (no LUNs etc were addd just the disks, auto include & format was on)

I hope the above is of some help.

Regards

Tim

[Ted Buis]

The VA7410 (1-2Gbit/sec FC) can have more "backend" performance capacity by 2X compared to the VA7400 (1Gbit/sec FC), so it could be faster than the VA7400 cited earlier assuming the drives are 2Gbit/sec FC. Consider also, that as you add more drives you get more "backend" I/O's per second up to a point. Since, you have only 23 drives, you are not yet at that point of diminishing returns. The balancing is supposed to be a background task that doesn't run when activity is heavy, so it might take longer to finish, but shouldn't be a problem. It would be nice to hear how much degradation was seen by the prior post. Don't forget to read the instructions for adding drives. See page 132 of http://h200001.www2.hp.com/bc/docs/support/SupportManual/c00088801/c00088801.pdf
I assume you have dual controllers.