Resilver two drives simultaneously to upgrade

[ChrisReeve]

Hi

I have a 9-drive ZFS2-pool (4TB WD Red), anre are planning on upgrading to 9x10TB drives. Everything on my NAS is backed up in the cloud!

What would be the best way to upgrade? I dont have enough extra space to temporary store everything currently on the server locally (approx 20TB).

One option is to replace one (or two) drives at a time. I know I will increase the risk of losing the entire pool if the resilvering process fails while I replace two drives at a time, but this will cut my resilver-time in half (I hope). Would you resilver one drive at a time, or two?

Keep in mind, I have everything backed up. The only consequence of a failure, is having to download everything from my online backup, which would take at least about a week, but I would imagine resilvering 9 times will take significantly longer than this.

 

[anmnz]

Are you able to attach an additional drive (or more than one) to your system? If so you can replace disks online without any loss of redundancy. The process is described in the FreeNAS user guide.

 

[ChrisReeve]

Are you able to attach an additional drive (or more than one) to your system? If so you can replace disks online without any loss of redundancy. The process is described in the FreeNAS user guide.

I didnt know that! I have two other drives I could use for that purpose, both 4TB or above. Will look further into that option.

 

[anmnz]

I have two other drives I could use for that purpose, both 4TB or above.

I meant that you could plug in one or more of the new 10TB drives that you are planning to upgrade to and use each of them to replace an existing 4TB drive. (I believe you can replace multiple drives in parallel though I haven't done it myself.) Then when you're done, remove the 4TB drives that you just replaced, plug in more 10TB drives, and repeat until finished. As explained in the user guide, doing it this way you maintain your level of redundancy throughout the process.