add drives

[ixidor]

normally when 2TB drives were around $70 i would not evan ask my question, i would just get another rive and be done with it. i have a case that easily holds 8 hard drives. i picked the power supplu specifically to power up 9 sata devices 8 hdd + 1 dvd. i have 8 2TB drives, but one has important data on it.

is it possible to set up the zfs array with 7 drives.
copy data to array.
add drive to array.
extend partition.
or some addition/combination that achieves the end result of 8 drives in the array?

 

[Milhouse]

is it possible to set up the zfs array with 7 drives.
copy data to array.
add drive to array.
extend partition.

You can't add drives to an existing vdev. Pools (or Volumes in FreeNAS parlance) consist of vdevs, which are groups of disks (one to many) with your chosen level of redundancy (striping, mirroring, RAIDZ1, RAIDZ2). A pool can consist of one to many vdevs, each vdev adding additional storage, and your data will be striped across all of your vdevs.

So there are two ways to expand pool storage in ZFS: 1) adding additional vdevs and 2) replacing drives in an existing vdev with drives of a higher capacity - once all the drives have been replaced ZFS (though not the current version in FreeNAS) will expand to use the available space.

or some addition/combination that achieves the end result of 8 drives in the array?

You could create a pool with a single RAIDZ1 vdev consisting of 4 x 2TB drives, copy your data to the pool, then add a second RAIDZ1 vdev to the same pool with the remaining 4x 2TB drives, giving you a pool consisting of two 4-drive vdevs. You would be able to suffer the loss of a single disk from either vdev, but if two disks in the same vdev failed you would lose all of your data, ie. the entire pool.

However if you want a single RAIDZ2 vdev consisting of all 8 drives (any two of which could fail without losing data), I can't think of an easy way to transfer your data without first obtaining an extra drive.

And if your data is really important, you should always have a backup in which case you shouldn't be facing this issue. A NAS is NOT backup.

 

[ProtoSD]

2) replacing drives in an existing vdev with drives of a higher capacity - once all the drives have been replaced ZFS (though not the current version in FreeNAS) will expand to use the available space.

Just a small clarification, the current version does allow you to expand after replacing all the drives. There was some confusion about this a little while back, but a few people here have posted that it actually worked for them. Sorry I can't reference the posts, but they're here if you dig enough.

 

[Milhouse]

Just a small clarification, the current version does allow you to expand after replacing all the drives. There was some confusion about this a little while back, but a few people here have posted that it actually worked for them. Sorry I can't reference the posts, but they're here if you dig enough.

That's good to know.

 

[ixidor]

In Linux, you could simply add a drive to the md0, then expand the partition. On that note, any suggestions for a home user to backup ~8Tb of data? it looks i would need to spend over $3000 for a LTO5 tape drive + tapes + controller, assuming i could get it to work under freenas. Add another array to make snapshots to? maybe in 6 months when drives come down in price.