RAID-10 - replace the raid controller

I have a RAID-10 configured on LSI Logic 9211-4i controller (4 disks). The controller seems to be faulty. Every few days it stops to work, Vmware logs this: Lost access to volume xxxxxxxx-xxxxxxxx-xxxx-xxxxxxxxxxxx (DATASTORE) due to connectivity issues. Recovery attempt is in progress and outcome will be reported shortly.. When this happen only server restart helps.

In theory RAID10 is two mirrors stripped. Is it possible to replace the controller to different without data loss?

Solution 1:

Did you heard "if you lose your controller you lose your data if you don't have the very same controller lying on the shelf"? That often is said as a disadvantage of hardware RAIDs.

Forget that. That is really distant past. Those incompetent ones who still saying that crap today just didn't heard anything about SNIA. And LSI Logic controllers often use a SNIA DDF on-disk metadata.

Your first option is to try another LSI controller. The first one to look is the same one but 8i (8 SAS ports instead of 4). Completely another LSI model should work too. I once connected disks from old DELL PERC (which is OEM LSI) to newer LSI controller and it assembled RAID array from those disks just as if it was created with itself.

Other option is to use Linux. Its praised software RAID driver md knows DDF format too, so it recognizes it and able to assemble and access virtual disks of that format. Just find any SAS HBA, connect disks and boot Linux there and look what's in the /proc/mdstat. That way you at least will be able to make a dump of assembled virtual disk to some new disk without RAID and run VMWare from it.

The hard way is to assemble RAID10 by hand, which is possible to do with Linux again. That's not too hard. Think of it as if that was RAID0 of RAID1's (striped mirrors); you have to identify a "mirror pairs", and take a disk from each pair. Then you have to guess stripe size, which is not hard, usually examining disks with some direct-access hex editor allows to do that almost instantly. Then you assemble software raid "by hand" with "no metadata" and you can dump your virtual disk.