Replacing drives, which option is better or faster?

TrueNAS General
1

Hello all, maybe this is a dumb question but i just want to make the bast move.

I have an 8x4tb pool and in the next days i will start to replace all disks with 12tb ones.

I think i have two options:

  1. remove one drive at time and “replace” it from GUI, then let ZFS rebuild data on it
  2. connect the new drive and “replace” it from GUI

which move is the FASTEST one?
Thanks

2

Not sure about faster but option 2 is safer.

3

yep, forgot to mention it.
i know is safer but i need to understand how rebuild works.

option 1 rebuilds data then perform a scrub?
option 2 just copies data then perform a scrub?

do i need to wait for the scrub to finish before replacing the next drive?

4

Both options perform a resilver; neither performs an explicit scrub.
Both options involve all the available drives; option 2 is not a “sector copy” of the still available old drive onto the new one.
You may as well take the safest route. I do not expect that it will make a difference on speed.

5

Again, there’s no “scrub” as such. Once the replace operation finishes, you can remove the old drive with no loss of redundancy. If you have room for two or more spares, you can replace multiple disks at the same time.

2 Likes
6

sorry, with scrub i meant resilver.
got confused writing.

okay, i will go with the safest option then, i have two ports still available

7

Which means you can safely replace two drives at a time

Btw, you may be interested in this post on parallel resilvers

1 Like
8

Thanks!
interesting reading, i will give a try.
Unfortunately my ASM1064+575 has a limited bandwidth