Stripe pool, migration to zraid - a bit of advice needed….

[Krebsy]

Ok, so I’ll be as brief as possible.

I’ve a dell r410 server with 4x2TB drives in a single striped pool. (Storage1)
I’ve homebrewed an external storage array with 4x2TB drives set up as a 3 disk plus one spare raid array. (Copyofstorage1)
I’ve also got a single 6TB drive (Main clone) as a tertiary array.

I want to change the stripe setup to a Raid array using 6x2TB drives and 2 hot spares, then leave the 6TB separate drive as an extra backup/snapshot pool.

So, the data in the main storage pool is 5TB, so could be cloned to the separate drive and the pool then built as required, but is their an easier way to do it just by adding the extra drives into the main pool without having to go through totally recreating things?

If I were to Just back up the data to the 6TB drive, what’s the best option to use to ensure all the server shares and config is preserved?

The OS sits on a separate sata drive and I’ve also got an ssd set up as a cache drive….

The hardware side is easy, the raid config is the challenge :).

Ta,

stu.

 

[sfatula]

You cannot change from striped to Raidz1/2//3/mirrors. WIth 6TB drives, a raidz2 would be suitable. You say you want 2 hot spares, well, that would be better done as a raidz3 with a hot spare then for a total of 8 drives including the hot spare if I understand correctly. That would have the same capacity as 4 striped mirrors (but you'd have no spare).

Mirrors have less fault tolerance than Raidz2/z3 but are easiter to add more drives to the pool.

Unlikely your cache drive will do anything unless you have limited memory on the server, which you didn't post specs of or even use case. Memory > "cache drive" in general.

On my server with 64GB RAM, I have > 99% arc hit rate meaning a "cache drive" would likely do nothing or possibly even reduce performance.

 

[Krebsy]

Would it be possible to do the following?

Single storage pool :- (12Tb storage in total (comprising 8 2TB drives - 6 for data 2 "spares" for Resiliency)

Vdev no. 1 (4 disks set up as raid RaidZ1) (internal server Hdds)
Vdev no. 2 (4 disks setup as raidZ1) (external array)

Seperate 6Tb backup/snapshot drive...

Just trying to see what's the best way to organise the storage I have, maximise the storage space and provide a degree of resiliency. I can stick another 3 Sata drives onto the Storage array expander once I source them.

Also, would there be any issues running 4 sas drives on one Storage array channel and 4 Sata on a seperate one? I'm powering the drives directly from the chassis and not from the Storage cabling etc.

Ta,

Stu.

 

[sfatula]

It is certainly possible to do as you say, though you'll be at higher risk than a simple single vdev using raidz2. Space will be the same as an 8 drive raidz2. So, it's only a loss of resiliency for what benefit?

The backup drive would be a single drive pool, it's not just a drive as it will have zfs on it also.