RAID 5 migration

[advapi]

Hello,
I'm selling my QNAP and I've to plan what to do with my 4x2TB raid5 (ext4)
I was planning to move to RAIDz1 but I've read I cannot add new disk..and I need one of those 2TB for dumping the data...so I can't add it later as a part of the raid am I right?
If I still use the old RAID5 will I be able to move it (using always freenas) on another system (intel->amd and viceversa)

Thanks in advance

 

[William Grzybowski]

Correct, you cannot add single disks to expand a vdev in ZFS.

FreeNAS cannot mount ext4, so you would have to transfer the data over network.

 

[advapi]

so what I've to do right now is

1. remove a disk from my raid and use if for taking data
2. mount the 3 disks on freenas machine and format they (RAID5 or Raidz1)
3. Transfer data to the raid via lan
4. if raid5 add the disk to the array?

Will I have problem moving the raid to another architecture (motherboard change for example)?
Thanks

 

[JaimieV]

Step 4 will not work in ZFS, as William says you cannot add single disks to expand a volume. Steps 1/2/3 are fine, but you'll end up with a 3 disk array of 4Tb usable space.

This may not be a bad thing - you can thereafter use the 2Tb disk as a backup destination for the RAIDZ, or as a non-RAIDed extra disk in your NAS (see discussion nearby about using a non-resilient single disk for backing up workstations to).

And your final question: if you use ZFS (eg RAIDZ1) there will be no issues - ZFS pools are transferrable not only between different motherboards etc but also between operating systems (well, BSD/Linux/Solaris, possibly OSX soon). All the info needed to run the pool is included on the disks themselves. I've no idea how UFS handles these things.