Drive migration

[rmccullough]

I have a Supermicro 2U (CSE-826A-R1200LPB) 12x 3.5" Drive Bays and Supermicro X9DRi-LN4F+. This motherboard has 2 SATA 3.0 connections on it.

I currently have a single pool made up of 9 drives configured in RAIDz2. I am looking to build a new pool with 6-8 drives, and then migrate my data.

With RAIDz2, my understanding is that I can remove 2 drives and the pool will still be usable. Would it be possible for me to do this:

1. Unload current pool (pool1)
2. remove 3 drives from pool1 (providing 6 empty drive bays)
3. insert 6 new drives
4. use 6 new drives to create a new pool2
5. remove 1 drive from pool2
6. add 1 drive from pool1 back (removed in step 2)
7. Load pool1 (in a degraded state, missing 2 drives)
8. copy data from pool1 > pool2
9. unload pool1
10. put 1 drive back for pool2 (step 5)

Will this work?

In step 10, will it automatically re-build that drive when I add it back?

If I cannot do this, I would need to use the onboard SATA 3.0 connectors temporarily. Is this a better option? I was hoping to not need to crack the case to do this.

 

[Heracles]

my understanding is that I can remove 2 drives and the pool will still be usable

Usable, Yes. Safe, NO!!!

I would need to use the onboard SATA 3.0 connectors temporarily. Is this a better option?

Yes. A Way better option. With extra space and extra drives, your pools can stay protected. To have a pool with 0 redundancy is never a good idea. Never do it by design (single drive vDev), do not rely on Raid-Z1 (no redundancy is the consequence of every single failure) and do not drop Raid-Z2 by 2 drives on purpose.

Should you have any problem while running without redundancy, you can loose up to everything. And because it is when you are messing up with things that bad things happen, you would be at very high risk here.

Also, be sure to update your backups before doing something like that. You do have full backups of your data don't you ? No single server, FreeNAS or other, can be more than a single point of failure.

 

[rmccullough]

Ok, but can I remove 1 drive from a raidz2 relatively safely?

This way I could use 4 drive bays from the SAS backplane and the 2 SATA 3.0 connectors on the motherboard to build a 6 drive pool and copy data from the old pool. Is that reasonable? I was hoping to not need to open the case to do this, but it seems like it will be required...

 

[Heracles]

Ok, but can I remove 1 drive from a raidz2 relatively safely?

Hi again,

For sure, to remove only 1 drive would be much safer. That way, you will keep a minimum level of redundancy. That low protection will be temporary and you would now need 2 simultaneous incidents to loose your pool instead of any single one. Still, never forget that backups are always required, no matter how much redundancy you put in a single server.

Good luck with your move,

 

[ChrisRJ]

[..] I was hoping to not need to open the case to do this, but it seems like it will be required...

I don't want to be rude, but I find this rational somewhat "strange". This is a major operation and we are not even talking burn-in phase yet. Deliberately adding risk here is simply beyond me.

 

[Chris Moore]

Ok, but can I remove 1 drive from a raidz2 relatively safely?

This way I could use 4 drive bays from the SAS backplane and the 2 SATA 3.0 connectors on the motherboard to build a 6 drive pool and copy data from the old pool. Is that reasonable? I was hoping to not need to open the case to do this, but it seems like it will be required...

Are you building a new system to put this new pool into?

In step 10, will it automatically re-build that drive when I add it back?

Yes.