Hi, This morning we added 10 new drives to our EVA 8k. The only systems on this EVA are running MS Exchange.
Less than five minutes after the addition of the drives I got a call from the email admin asking if adding drives could cause performance to slow for the systems. I told him it shouldn't, but I would check the EVA and it's logs.
The Exchange guys run MOM, which was reporting that all 10 Exchange systems were having slow disk I/O performance. This lasted about 15mins. During this time CV-EVA showed no issues, in either the GUI or logs. And physically there were no indications (i.e. flashing lights/beeps). And we don't have the EVA automatically add drives to the disk group. And our FC switches (cisco MDS) logged nothing.
My questions are, would there be a performance issue when adding drives? If so, why? If not, what else might be going on?
I think I recall seeing a procedure quite a while back for adding disks that recommended adding them one at a time and then waiting longer than your "disk replacement delay" value (seen on CV EVA "Initialized Storage System Properties" page) between each one. To be extra safe, you could go to the disk enclosure page under "hardware" and verify that the new drive has been discovered in its drive bay between additions.
This was old enough that I'm sure it was an EVA3K/EVA5K procedure and I've no idea if it applies to the EVA8K, but from what you saw it seems that maybe it does.
Absolutely, Mark, the suggested time to wait between disk inserts is up 90 seconds or better: wait until the activity indicator stops flashing, according to the EVA 4000/6000/8000 user guide.
I, too, check within CV-EVA whether the new disk has been recognized and a proper name assigned before I insert the next disk. In earlier revisions I had experienced duplicate disk names :-(
Thinking ahead a little... if you are talking about AFTER you added the drives to the Disk Group that is hosting the Exchange data, then ABSOLUTLEY there can be a performance hit. While the Disk group levels out, copying data from the original disks to the new disks to spread it out amongst all the disks, there will definitely be a performance decrease until it finished, especially if there is alot of data and the servers are hitting the disks hard (lots of i/o).
Steven
Steven Clementi HP Master ASE, Storage and Clustering MCSE (NT 4.0, W2K, W2K3) VCP (ESX2, Vi3, vSphere4, vSphere5) RHCE NPP3 (Nutanix Platform Professional)
Now that you mention, it I do remember something along the specs you've posted. Seems like such a device should be quicker. Oh, well. We'll make a note ( rather, a big sign :) ) of it.
