[Gluster-users] New GlusterFS Config with 6 x Dell R720xd's and 12x3TB storage

[Brian Candler]

On Tue, Dec 04, 2012 at 04:33:30PM +0000, Mike Hanby wrote:
> Thanks Brian. I'm going to test the multiple volumes suggestion today.
> 
> Regarding the underlying storage, the 12 x 3TB disks are configured as a single RAID6 that is presented to the OS as 10 x 3TB disks via the Dell PERC controller. So the OS sees /dev/sdb,c,d,e,...
> 
> I did this because I was under the impression that all bricks have to be the same size. So for future expansion I didn't want to get into a situation where additional servers had to come configured with exactly 30TB of usable storage.

Yes, if you have a distributed or replicated volume with uneven bricks then
you will waste space in the larger ones.

At least if you plan for having servers having a multiple of 12 disks, you
can make them all have N x 12-disk RAID6 sets. The problem is if you decide
you want to include servers with smaller numbers of disks than that.

Also, remembering that future servers might have 4TB or 5TB drives, it does
become hard to do forward-planning (creating dozens of 1TB bricks will be
even more painful). This is a use case which gluster does not address well.