Re: [zfs-discuss] zpool scalability and performance

2011-01-15 Thread Roy Sigurd Karlsbakk
the ZFS_Best_Practises_Guide states this: Keep vdevs belonging to one zpool of similar sizes; Otherwise, as the pool fills up, new allocations will be forced to favor larger vdevs over smaller ones and this will cause subsequent reads to come from a subset of underlying devices leading to

[zfs-discuss] zpool scalability and performance

2011-01-13 Thread Stephan Budach
Hi, the ZFS_Best_Practises_Guide states this: Keep vdevs belonging to one zpool of similar sizes; Otherwise, as the pool fills up, new allocations will be forced to favor larger vdevs over smaller ones and this will cause subsequent reads to come from a subset of underlying devices leading

Re: [zfs-discuss] zpool scalability and performance

2011-01-13 Thread Benji
The way I understand it is that you should add new mirrors (vdevs) of the same size as the other vdevs already attached to the said pool. That is, if your vdevs are mirrors of 2TB drives, don't add a new mirror of, say, 1TB drives. I might be wrong but this is my understanding. -- This

Re: [zfs-discuss] zpool scalability and performance

2011-01-13 Thread a . smith
Basically I think yes you need to add all the vdevs you require in the circumstances you describe. You just have to consider what ZFS is able to do with the disks that you give it. If you have 4x mirrors to start with then all writes will be spread across all disks and you will get nice