On 10/26/2016 02:02 PM, Gandalf Corvotempesta wrote:> 2016-10-26 22:59 GMT+02:00 Joe Julian <joe at julianfamily.org>: >> Personally, I prefer raid0 bricks just to get the throughput to saturate my >> network, then I use replicate to meet my availability requirements >> (typically replica 3). > Isn't the ZFS cache on SSD enough to saturate the network? > I'll use replica 3, but I don't feel safe having the whole node in > RAID0, a single disk failure means the whole node to heal from scratch > and commodity disks are prone to failI just add enough disks to saturate (and I don't like zfs, personally) per-brick. So with 30 disks on a server, I typically do 5-disk raid-0 and create 6 bricks per server.
2016-10-26 23:04 GMT+02:00 Joe Julian <joe at julianfamily.org>:> I just add enough disks to saturate (and I don't like zfs, personally) > per-brick. So with 30 disks on a server, I typically do 5-disk raid-0 and > create 6 bricks per server.30 disks per server? which chassis are you using? Why don't you like ZFS? I admit, I prefere to use plain XFS and mdadm, but ZFS has some really usefull features like bitrot detection, SSD cache and so on.
On 10/26/2016 02:04 PM, Joe Julian wrote:> On 10/26/2016 02:02 PM, Gandalf Corvotempesta wrote: >> 2016-10-26 22:59 GMT+02:00 Joe Julian <joe at julianfamily.org>: >>> Personally, I prefer raid0 bricks just to get the throughput to >>> saturate my >>> network, then I use replicate to meet my availability requirements >>> (typically replica 3). >> Isn't the ZFS cache on SSD enough to saturate the network? >> I'll use replica 3, but I don't feel safe having the whole node in >> RAID0, a single disk failure means the whole node to heal from scratch >> and commodity disks are prone to fail > > I just add enough disks to saturate (and I don't like zfs, personally) > per-brick. So with 30 disks on a server, I typically do 5-disk raid-0 > and create 6 bricks per server. >And yes, they can fail, but 20TB is small enough to heal pretty quickly.