HPE EVA Storage

EVA 8100 Design Question / 146, 300 and 600 GB Disks


EVA 8100 Design Question / 146, 300 and 600 GB Disks

Hi, we have an EVA 8100 (it was upgraded from a EVA 5000) with 200 hundred disks. (120) 146 GB and (80) 300 GB disks. They are divided evenly between 2 diskgroups right now. As we are starting to max out the total capacity of our EVA (240 disks) we are looking into buying 600 GB 15,000 RPM disks. My question will be: Should we create a third disk group exclusively for the 600 disks?? or we should distribute them in our 2 diskgroups? or just in one?

one thing that we im afraid is that right now, when we have to replace a disk or insert a new one, it takes forever (like 5 days) the whole leveling and creation process. if we add more disks to our already BIG diskgroups, that won't help!! we also know that the best practices recommend using as few diskgroups as possible.

I want to know your expert opiniongs. Money is a factor! I can't go out and replace, for example, all of the 146 GB disks. So keep this is mind!

Thanks for all your help!

Trusted Contributor

Re: EVA 8100 Design Question / 146, 300 and 600 GB Disks

Best Practices say to use less disk groups but also on Generation 2 EVA's having more than 80-100 disks in a group does not increase the performance. I mean the performance increase is not lineer to disk # in the group. Also you are reducing the redundancy of your disk group by having high number of disks because you can only have double protection as spare, not more.

Also by adding 600G drives to your present groups will also double the protected area as spare because the reference is the biggest cap drive in the group.

If I were you I would create a new group with single protection level. It wont need any leveling time and does not effect the present groups protection level.
Víctor Cespón
Honored Contributor

Re: EVA 8100 Design Question / 146, 300 and 600 GB Disks

Mixing disks of different sizes on a disk group will not give you the sum of all the capacities.

Right now, having 146 and 300 GB disks, the 300 GB disks will not be fully used. The 600 GB disks will likely have even more unused space.

But having a disk group with a few 600 GB disks will mean less performance for the vdisks on that disk group.

You can purchase a good quantity of 600 GB disks, or move only big, seldom accesed vdisks to the new disk group.