Expand EVA4000 while at 99% occupancy (62 Views)
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Occasional Contributor
ManagedServices
Posts: 3
Registered: ‎12-09-2009
Message 1 of 4 (62 Views)

Expand EVA4000 while at 99% occupancy

We have an EVA4000 with a disk group with 20 disks. The total raw capacity is 2459.9GiB, with 12GiB unallocated.

Most of the storage is allocated to two Vdisks ( 560GiB and 800Gib) used as VMWare Datastores

My questions:
- What risks do we have adding disk into the disk group at this level of occupancy?
- Is it recommended that we remove some VDisks to reduce the occupancy before we add additional disk into the "Disk Group"?
- What is the recommended occupancy level before we place the "Disk Group" at risk of failure?

Thanks and regards,
Marc
Respected Contributor
Prokopets
Posts: 395
Registered: ‎02-22-2008
Message 2 of 4 (62 Views)

Re: Expand EVA4000 while at 99% occupancy

Marc,
it's not a good idea to use more than 95% of raw space on EVA.

>- What risks do we have adding disk into the disk group at this level of occupancy?
If i understand you correctly, you want to add physical disk in the disk group - that's ok and shouldn't be a problem.
>- Is it recommended that we remove some VDisks to reduce the occupancy before we add additional disk into the "Disk Group"?
It's not necessary.
- What is the recommended occupancy level before we place the "Disk Group" at risk of failure?
95%

Your EVA is quite old, so i recommend you to check the controllers and disks firmware version and upgrade it to last one before you add disks.
Honored Contributor
Víctor Cespón
Posts: 2,397
Registered: ‎11-09-2007
Message 3 of 4 (62 Views)

Re: Expand EVA4000 while at 99% occupancy

Having disk space used is not going to make the disk group fail or cause data loss by itself. This is a RAID system after all.

Usually the disk group has "Disk drive failure protection" set to Single. This means that you really have the space equivalent to 2 disks free, but this space is reserved and not available to create vdisks.

If the disk group is to full you can face the following situations:

- A disk is having a lot of errors and interrupting the loops, but it not failed yet. You cannot ungroup and replace it because you have no space

- A disk fails, rebuild process is not started until you replace the disk because there's no spare space available.

- The disk group becomes inoperative because some disks reach 100% occupancy while rebuilding. In this case you have to delete or shrink vdisks to get out of it.

- Leveling cannot be done because there's no free space. In this situation you cannot add or remove disks. You must free some space.
Frequent Advisor
Danel_1
Posts: 73
Registered: ‎08-24-2005
Message 4 of 4 (62 Views)

Re: Expand EVA4000 while at 99% occupancy

hi ,

You can add new disks one by one with one minute delay.
Wait for comamnd view detect the new disk and assign a logical disk name.

the final step is to group all disks in one action to have only one leveling.

it' s not necesaary to delete vdisk before this .

the only recommandation is to put the same disk size , and to verify the fw disk in ungroupped Disk Group.

Didier DANEL
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