EVA 4100 disk group extension - capacity limitations before extanding

[Andrey Ponomarev]

Dear Colleagues,
One question.
I have EVA 4100 all enclosures with 300Gb FC disks.
Unfortunately we have capacity problem and decided to use 600 Gb FC disks. On my system single level protection - that means that after inserting first disk system will demand 1.2 Tb instead 600 Gb in this time.
So my question is if I have only 1.2 Tb of current free space in RAID0 for Disk Group
which I'm going to expand. Will it be a problem for me? Does system permit me to extend disk group with such free capacity?

[Uwe Zessin]

You could set the protection level to NONE - when reconstructing, the EVA will draw from free space in the disk group anyway before it touches that from the "protection level".

[Andrey Ponomarev]

Yes, but it is little bit dangerous to have zero protection level. As I understand it should stay till leveling finish. It is 3-4 days to my system :(
Sorry Uwe, I didn't catch second part of your advice, what did you mean? Сan I add 600Gbs disk in my situationÑ

[Uwe Zessin · Accepted solution]

The protection level is only a "highwater mark" that prevents you from filling the disk group "too much" so that not enough capacity is left for reconstruction data after a disk drive failure. The pr-level does not provide any protection additional to the virtual disk's VRAID.

When a reconstuction is necessary and there is "free space" in the disk group (in addition to the protection level), the EVA will first use up that space to keep the protection level as long as possible (at least that is what I have seen).

So you could theoretically do the space management yourself, but it is safer to tell the EVA to do that during normal operation.

[Andrey Ponomarev]

Ok, Thank you!