Adding 2 drives to my pool

[Fish]

Currently, I've got 2 WD Red 2TB drives in a mirror for my main volume. I purchased 2 more and would like to add them to the pool. I want to set it up as the RAIDZ2 (I believe that's preferred to RAIDZ3?) version of RAID10. From what I gather, I can do this but there are some things to keep in mind:

• If I add drives and change the pool configuration, all the data will be lost so I have to migrate it off first
• Once the drives are added, they can never be removed from the pool

Is this something that will work? If so, I'm also wondering what the easiest way to migrate my data is, and if there are any advanced settings I should change on the drives? Reading through the forums, it looks like these NAS drives should have most of that stuff built-in and enabled by default.

Thanks guys, you're always so helpful.
Fish

 

[Fish]

Reading this article it sounds like using mirrored vdevs might be better? So 2 vdevs of 2 drives. I'm really trying to get 2 drive parity but also maximize performance and minimize resilvering time.

 

[nightshade00013]

It would not be possible to make a four drive RaidZ2 pool without destroying the disks you have now. You can not add or remove disks from a vDev and you can add but not remove vDev's to a pool.

You could set the two drives in a mirror the same as you already have and add that vDev to the pool. That would be as close to a Raid10 as you would get.

RaidZ2 is preferred over RaidZ1. You could do a RaidZ3 if you want more redundancy. Look at it this way, a RaidZ1 vDev can lose one drive and keep all your data safe but the loss of a second drive will result in the loss of all the data. A RaidZ2 vDev can lose two drives and not lose data but the loss of a third drive will result in data loss, and a RaidZ3 vDev can lose three drives and survive but four drives will result in data loss.

It would be preferable to have your drives in a RaidZ configuration rather than to have mirrored pairs though. You will basically have the same amount of storage but with a RaidZ2 you could lose any two drives while having a two sets of mirrored drives could lose one drive on either vDev but not two drives on a single vDev.

There is a lot explaining everything I went over here: https://forums.freenas.org/index.ph...ning-vdev-zpool-zil-and-l2arc-for-noobs.7775/

And make sure you burn in the new drives before you even get started using them: https://forums.freenas.org/index.php?threads/how-to-hard-drive-burn-in-testing.21451/

The red drives should have things setup pretty well by default for your system but you can still check the idle timer with the info here: https://forums.freenas.org/index.php?threads/hacking-wd-greens-and-reds-with-wdidle3-exe.18171/

Migrating your data will require another drive that you can transfer it all to or a couple drives that you can split it up on until the old pool is destroyed and the new one created and ready to store data. The options for doing that are numerous including but not limited to rsync, manually transfer to another computer with samba/NFS. The best option there is one you understand and trust.

As far as the article you are looking at, while a bunch of mirrors will be faster they will not have the fault tolerance a raidz will have.

 

[Fish]

Wow, thank you for all that information. It sounds from that like RaidZ2 is what I want to go with. In terms of actual steps to carry out to make 2 vDevs like that, should I use the command line tools to do that? The FreeNAS GUI doesn't seem to reference vDevs at all and I would like to make sure I configure it exactly how I need to.

I'll be sure to burn the new drives and as well as the 2 that I've been using for the past 2 months that never got that done.

In terms of migrating the data, I'm probably going to add 2 750GB drives temporarily in a mirror and move the data to there. Is Rsync able to use the local machine as both a source and destination? I could just use cp but I wouldn't get any progress information....

 

[Bidule0hm]

should I use the command line tools to do that?

You should NOT use the CLI. You should use the GUI (which refer to pools as volumes).

Is Rsync able to use the local machine as both a source and destination?

Yes, no problem.

 

[Fish]

I'm still a bit hazy on the specifics to go through to configure the drives. Could someone give me just a general walkthrough to configure exactly as above? Also, what's the best way of going about Rsync'ing my data to a temporary pool to see the status without having to keep a machine connected through SSH the whole time? Screen maybe?

 

[Bidule0hm]

Go to the storage tab and click the volume manager button, then just make your volume with the drives and the vdev type you want.

Look at tmux, you can launch a tmux session then disconnect your SSH session and you'll still have access to the tmux session once you reconnect with SSH ;)

 

[Fish]

Okay, tmux seems like a pretty good solution. Onto my next question... Can I just rsync the main volume inside of the volume on my temp array?

Here's what I've got currently:

So can I just do this:

Code:

rsync /mnt/vol1 /mnt/volTempMirror/vol1

then add my disks and do the opposite?

 

[Bidule0hm]

Yes, you can do that. Just be careful with the trailing slashes because rsync is a bit touchy with that (vol1 and vol1/ isn't the same thing).

 

[BigDave]

RaidZ2 is preferred over RaidZ1. You could do a RaidZ3 if you want more redundancy. Look at it this way, a RaidZ1 vDev can lose one drive and keep all your data safe but the loss of a second drive will result in the loss of all the data. A RaidZ2 vDev can lose two drives and not lose data but the loss of a third drive will result in data loss, and a RaidZ2 vDev can lose three drives and survive but four drives will result in data loss.

@nightshade00013 you might want to correct your original post for accuracy.

 

[nightshade00013]

@nightshade00013 you might want to correct your original post for accuracy.

Ok fixed.