EVA4400 HDD upgrade??

[rvent]

Hello,

We have an EVA4400 and currently have 5 empty bays in each disk tray. All the HDDs that we have are 400GB.

Is it possible to add larger disks (say 1TB) to the 5 empty bays in both trays and add them to a separate disk group and be able to fully utilize the maximum capacity of the disks?

I believe that if we add larger disks to the EVA and assign them to the existing disk group, we would only be able to use the lowest size in the group, correct?

[Steven Clementi · Accepted solution]

"Is it possible to add larger disks (say 1TB) to the 5 empty bays in both trays and add them to a separate disk group and be able to fully utilize the maximum capacity of the disks?"

Yes. You need a minimum of 8 disks to create a disk group.


"..we would only be able to use the lowest size in the group, correct?"

No. You can mix disk sizes withen the same disk group. You can NOT mix disk types though. (Fibre vs. FATA). In your case, I think you have 400GB Fibre disks and want to add 1TB FATA, so you will have to create a new disk group.


Steven

[rvent]

So let me see if i got it right:

Tray 1 has 5 empty slots and tray 2 has 5 empty slots, this would equal 10 which would meet the requierement of 8 disks to create a new Disk Group, correct?

And so let's say i get the same disk type, but different disk size (5 per each tray would be 5TB raw at 1TB per disk), this would increase my total size by 5TB, correct?

And 2 more questions: Would it be better to create a new disk group with the new upgrades instead of adding them to the same Disk Group?

Can VDisks be moved between Disk Groups? Let's say i have a Vdisk "XenServ-OSdisks" and resides in DiskGroup1, i then have a DiskGroup2 and decide that we need to start upgrading the Disks in DiskGroup1, other than the Xen operation, could i just move "XenServ-OSdisks" to DiskGroup2..?

Thanks!

[Steven Clementi]

"Tray 1 has 5 empty slots and tray 2 has 5 empty slots, this would equal 10 which would meet the requierement of 8 disks to create a new Disk Group, correct?" - Yes

"And so let's say i get the same disk type, but different disk size (5 per each tray would be 5TB raw at 1TB per disk), this would increase my total size by 5TB, correct?" - I think the largest Fibre Disk you can get currently is 600GB. 600GB*10 = 6TB Raw.


"Would it be better to create a new disk group with the new upgrades instead of adding them to the same Disk Group?" - Best Practice for Cost and Performance is to have the least amont of disk groups. In other words, it would be best to add disks to you existing disk group(s), if possible. There are some "gotcha's" though and we can discuss if necessary.

"Can VDisks be moved between Disk Groups? Let's say i have a Vdisk "XenServ-OSdisks" and resides in DiskGroup1, i then have a DiskGroup2 and decide that we need to start upgrading the Disks in DiskGroup1, other than the Xen operation, could i just move "XenServ-OSdisks" to DiskGroup2..?" - Simple answer is No, not directly at least. First, you would not need to move vdisks since you can upgrade disks live in a disk group. When you add in a disk to a group, the EVA "Level" the data in the disk group.. re-distributing all the data among all of the disks. That being said, you can mix different size disks in the same group and all of the space will be utilized. Keep in mind that larger disks will contain more data than the smaller disk, keeping the same utilization percentage as the rest of the disks. This will also increase the reserved Disk Protection space for that group since the group now needs to protect a larger disk. (Again, we can go into more detail if necessary). Second, you can remove the older disks live as well and the EVA will re-level the data.

If you wanted to perm move data, you could use Business Copy to make a Snapclone of the disk and then swap presentation to the new vdisk. You can snapclone across disk groups.


Steven

[rvent]

If you dont mind, could you provide a link for me to get more details or if you have time could you mention the gotchas.

Would there be that much of a performance hit when using 2 Disk Groups?

So basically i could just add the drives to the EVA and assign them to the same Disk Group, then just swap the older ones with newer disks and the EVA will just redistribute the data, correct?

Thanks for all your information.

[Henry A.C. Jansen]

If you can wait a little more.. the new XCS Firmware for the EVA4400 (in combination with CVE 9.4) is capable of migrating vdisks between diskgroups and even Vraid levels without downtime... :)