Recover Thecus RAID5 on FreeNAS?

[Andreas Pohling]

Hi guys,

I do have a THECUS N5500 NAS, however, the hardware died recently, it does not start anymore.

Would it be possible to assemble the 5 RAID disks to another hardware and recover the existing RAID5 array?

Any idea welcome.

Regards

 

[m0nkey_]

If your array was ZFS, you might have a chance, however the ZFS feature set needs to be compatible with FreeBSD. You'll need to do some homework before trying.

If you set-up a XFS or EXT volume, then FreeNAS will not help you.

 

[wblock]

FreeNAS can import some ext volumes. But the first contact should be the vendor, to find out what filesystem is used on those disks, and what sort of RAID metadata is in place.

 

[snaptec]

The n5500 may use Linux software raid aka mdadm. Google that!
FreeNAS cannot import mdadm raids.
You can setup up an ubuntu/Linux box.
mdadm --scan and maybe it will show up. Then copy it away.


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[Pezo]

Sorry to resurrect this thread, but I have pretty much the same problem.

My Thecus NAS died and now I'm left with a 7 disk RAID5 array (mdadm, ext4). Since FreeBSD apparently doesn't do mdadm, I had another idea for which I would love to get some input. I don't have another machine where I can put 7 disks at once (at least not easily), so I was thinking this:

• Set up FreeNAS and create a ZFS volume on a new set of disks (which are in the same machine as the old disks).
• Boot the machine with Arch Linux or somesuch, mount both the FreeNAS ZFS volume as well as the Thecus mdadm RAID5 array, and copy over the data (ext4 -> ZFS).

Now I don't have any experience with ZFS (neither on Linux nor on FreeNAS), so I don't know whether they even use compatible ZFS implementations. What do you guys think?

 

[danb35]

I don't know whether they even use compatible ZFS implementations.

I believe they do; they're both based on OpenZFS.

What do you guys think?

On its face, it sounds like something that should work. It should be easy enough to test with just a single disk for the ZFS pool. But you would want to create the pool through FreeNAS, not with some other OS.

 

[Pezo]

I believe they do; they're both based on OpenZFS.

What would happen if they're not compatible? I'm assuming it would just not mount instead of being corrupted somehow?

But you would want to create the pool through FreeNAS, not with some other OS.

That's what I thought, yes.

 

[danb35]

What would happen if they're not compatible? I'm assuming it would just not mount instead of being corrupted somehow?

That's what I'd expect--either it would work or it wouldn't. If a pool created with the current version of FreeNAS doesn't work with your preferred flavor of Linux, the next thing I'd try would be to create one with 8.3--that uses an older version of OpenZFS which might be more compatible. But try it with FreeNAS 11 first.

 

[Pezo]

So I tried this with Arch Linux on a USB drive and everything went just fine.

However, after copying some stuff over, about the same amount as I have RAM in that machine, writing to the ZFS volume got really slow, like 30MB/s to a raidz2 with 6 drives. Could this be a problem with the Linux ZFS implementation (I noticed the arc_reclaim process hogging some CPU, which I don't see on FreeNAS even after writing a few 100GB)?
Write speed was never that great to begin with, just 150MB/s, would have expected more...

edit: I can open a new thread if that's becoming too off-topic.

 

[Pezo]

Bump.
Also I was thinking of creating the ZFS volume under Linux instead of FreeNAS, but I don't think that's a good idea since zpool status on Linux tells me there are features not supported by the pool and that I can upgrade it. So FreeNAS probably wouldn't be able to read the pool then.