HPE Storage Users Group

We are planniing to use 3par only with fully provisioned vv-s.

Is there any guidance available how much disk space should we leave free for the 3par to operate normally?

carlos1800 wrote:We are planniing to use 3par only with fully provisioned vv-s.

Is there any guidance available how much disk space should we leave free for the 3par to operate normally?

As long as you plan to replace failed drives when they fail and are not going to use snapshots or replication I would say 99.9%.

Also depending if you plan to never expand the size of a VV, even if it fills up, without buying more disks (consider the turn around time for an order and if there are constraints on parts).

You'd need to have a very stable application environment, without upgrades/updates to manage that though or lots of free space on every VV.

ailean wrote:Also depending if you plan to never expand the size of a VV, even if it fills up, without buying more disks (consider the turn around time for an order and if there are constraints on parts).

Just to confirm: If we buy new disks to increase the storage capacity, and 99% of the 3par storage capacity is used by fpvv-s, the expansion of a vv is still possible? Ie. the system doesn't requires some headspace for the growvv to complete?

By default all disk space becomes a single pool of space, so when you add new disks they will just expand the pool, allowing growth of any VV.

There are a few things to take into consideration though, if you want to expand a VV by 1TB don't just buy 1TB of new raw disk. You have to take into account a small amount of system space on each disk, a chunk of spare space on each disk and a percentage of parity space for the VV.

Once new disks are added you may also need to spread the data out so it evenly distributed across all disks, this is often automated but might take a little while depending on how busy the system is.

Personally I'd probably aim at a 90-95% fill with the fpVVs just so there's some margin, the system can rebalance data depending on performance usage but that does require a bit of free space. It also allows you to expand a VV in an emergency if needed.

HPE do have sizing tool called NinjaSTARS, it allows you to build virtual 3PAR system and play with the number of disks, RAID setting etc and gives a reasonable estimate of the actual usable disk space to expect (it does include savings from thin provisioning, compression and dedupe but you can turn most of that off to see what fpvv would provide).

Great, thanks.