Hi all,

I've read and watched various guides and videos in regards to data array expansion with parity. All the guides really talk about starting the replacement of the parity drives with a much larger drive than the data drives first. After the parity rebuilds then rebuilding the data drives with the larger drives is possible.

But in my current case I have two parity drives. So if I rebuilt the parity drives 1 by 1 (of course it would take way more time) I can ultimately upgrade the whole array and just do the swaps one by one until the entire array and parities are all up to the new capacity?

But then part b of the question is being that I have two parities...... could I in theory just pull both parity drives and swap with the larger capacity to start the parity rebuild on both parity drives with the larger drives before moving onto the data array instead of one at a time? Or is doing this method 1 at a time generally safer?

Edited January 7Jan 7 by IonNuke

You can rebuild 2 drives at the same time. Both parity, then 2 data drives, etc.

Probably not very risky since you will still have the original data drives.

You must always have good (enough) backups of course.

Parity is not a substitute for backups.

Be careful with connections. And if you're going to introduce several new drives in a short time, might be a good idea to test them.

7 hours ago, trurl said:

Be careful with connections. And if you're going to introduce several new drives in a short time, might be a good idea to test them.

Careful with connections? I'm not sure I follow.

As an overview I have 12TB x6 for the data and x2 for parity. I thought maybe since I had two parity I can build both parity at the same time with two new larger drives. I read for this method the parity drives have to be first on the upgrade for obvious reasons. And then data array drives for rebuild can be done after that.

I think the "risk" that lives in my head is what if something goes wrong during the rebuild. It's all feeding through a Perc H310i HBA. Part of me also thought maybe I can swap out the HBA to a Perc H710i during the rebuild steps but I figured probably not mess with the hardware altogether. Maybe hardware swap would be after I stabilize the array first. Thoughts?

2 minutes ago, IonNuke said:

Careful with connections? I'm not sure I follow.

Power/SATA/SAS connections to the drives. By far the most frequent problem we see when replacing disks is the connections to the drives, whether to the replaced disks, or to other disks getting their connections disturbed.

5 minutes ago, IonNuke said:

the "risk" that lives in my head is what if something goes wrong during the rebuild

Usually you can fix whatever the problem is and try again. In any case

7 hours ago, trurl said:

you will still have the original data drives

If you ever see "unmountable" on any disk, you have a problem that needs to be fixed before rebuilding.

9 hours ago, trurl said:

If you ever see "unmountable" on any disk, you have a problem that needs to be fixed before rebuilding.

I've only come across that once. And in that situation I pulled the drive and swapped with a new one and the rebuild took another 19 hours before it was up and running.

Oh as a side note..... have you ever used any of the high capacity hard drives that utilize CMR with ePMR writing technologies as a parity drive? Also want to thank you so much for answering my questions and concerns helping move towards a better direction XD

1 hour ago, IonNuke said:

I've only come across that once. And in that situation I pulled the drive and swapped with a new one and the rebuild took another 19 hours before it was up and running.

Rebuild is not the way to fix Unmountable, and almost never does. The correct action is to check filesystem and repair. In fact, we always recommend against rebuilding until check filesystem and repair has been done, because rebuilding an unmountable disk usually results in an unmountable disk.

This is why I mentioned it, because rebuild is the wrong action to take.

So the next time unmountable disk shows up just repair it and check the whole array again? And after that if it fixes it the unmountable will effective mount again?