On 9 December 2014 at 20:22, Tim Hamilton <hamilton.tim@gmail.com> wrote:
If any of you had my hardware, how would you construct your storage layout?
The more disks you have, the higher the chance of having a disk failure. The older the disks you have, the higher the chance of having a disk failure. I like low-maintenance, high-reliability solutions where they fit well, so I would aim for a system that uses a few, large, disks, and plan to replace them in 2-3 years. I'd start by trying to estimate how much storage I might want within the next couple of years. Let's say I want to have 2TB of storage. In that case, I'd purchase two 2TB drives, mirror them in btrfs, done.[1] mkfs.btrfs -m raid1 -d raid1 /dev/disk/by-id/foo1 /dev/disk/by-id/foo2 Time goes by, the amount of data I'm collecting ramps up hugely, I need more space. So, I'd buy a couple of 4TB drives, and add them to the pool and then perhaps rebalance: btrfs device add /dev/disk/by-id/foo3 /mnt btrfs device add /dev/disk/by-id/foo4 /mnt btrfs balance start /mnt Later, I'd remove the original drives as they were getting old, and probably look at replacing them with bigger drives. btrfs device delete /dev/disk/by-id/foo1 /mnt btrfs device delete /dev/disk/by-id/foo2 /mnt Anyway, this all works, at least on the 3.17 kernels. An aside: on much earlier ones I noticed that the free space reported by 'df' was always quite wonky for RAID1 btrfs filesystems, but it seemed to get fixed eventually. Footnotes: 1: I'd actually buy three drives, with the third an externally housed one used for off-site backup.