Upgrading and Replacing Hard Drives With Different Speeds

[Chris Moore]

PS. If you have a means of opening an SSH session to your FreeNAS system, you might use Midnight Commander to easily copy data from one pool to the other. Here is some information on MC:
https://www.ixsystems.com/documentation/freenas/11.2/cli.html#midnight-commander
and a video:
https://www.youtube.com/watch?v=lWu2R9cn_b8

 

[Digitaldreams]

The ideal thing to do is wait until you have all six drives, then create the RAIDz2 vdev with all six drives in it. The only thing you can do with two drives is create a mirror vdev. Although you can add a mirror vdev to a RAIDz2 vdev, mixing a pool like that is strongly discouraged and I know that the GUI will warn you about it and it might not even let you. I have not tried to force that.
The reason for NOT doing it is this, it mixes parity levels. The RAIDz2 is double parity while the mirror is single parity. The thing you could do is create your new pool as two mirror vdevs, using the drives you have, then add another mirror vdev when you get the additional drives. The system will allow that with no errors as all vdevs would be single parity and you would end up having three vdevs, which would give you higher random IO potential.

This sentence indicates some misunderstandings. I would suggest you go to these resources and review them again:

Slideshow explaining VDev, zpool, ZIL and L2ARC
https://forums.freenas.org/index.ph...ning-vdev-zpool-zil-and-l2arc-for-noobs.7775/

Terminology and Abbreviations Primer
https://forums.freenas.org/index.php?threads/terminology-and-abbreviations-primer.28174/

My understanding of your situation is this. You currently have a storage pool (zpool) that is made up of a single vdev of 4 drives in RAIDz1.
You want to expand your storage capacity and move to RAIDz2 for greater protection against single disk failure.
The steps involved would be.

1. Connect all the new drives to the system and do burn-in testing on them.
2. Create a new storage pool using the new drives.
   https://www.ixsystems.com/documentation/freenas/11.2/storage.html#creating-pools
3. Copy all data from the old pool to the new pool.
4. After all the data is copied, in the GUI, there is a way to "Detach" the old pool
   https://www.ixsystems.com/documentation/freenas/11.2/storage.html#export-disconnect-a-pool
5. Physically remove the old drives.

Yeah I wont even consider mixing parity levels or adding in a mirror vdev as you said. I'd also like to stick to a straight up RAIDz2 format but I can't wait until I have all 6 disks. I'm not sure when I will be able to afford another (2) drives and the need for that shouldn't come for a while I'd suspect. Couldn't I just create a new pool with in a RAIDz2 vdev format when now with the (4) 8TB disks and once I have all 6 disks, just restore the data from my backup source?

PS. If you have a means of opening an SSH session to your FreeNAS system, you might use Midnight Commander to easily copy data from one pool to the other. Here is some information on MC:
https://www.ixsystems.com/documentation/freenas/11.2/cli.html#midnight-commander
and a video:
https://www.youtube.com/watch?v=lWu2R9cn_b8

Yes, I can SSH in. That's great info, thanks.

 

[Chris Moore]

Couldn't I just create a new pool with in a RAIDz2 vdev format when now with the (4) 8TB disks and once I have all 6 disks, just restore the data from my backup source?

Yes. You can do that. If you are willing to copy the data back into the pool again.

 

[Digitaldreams]

Yes. You can do that. If you are willing to copy the data back into the pool again.

Cool, I think that's my plan then. I've done some searching in the forums about burn in process and using SMART tests to do it. I need to investigate further. I'll probably start by combing through the famously shared resource guide. https://forums.freenas.org/index.php?resources/building-burn-in-and-testing-your-freenas-system.38/