Re: recovery problems, might be driver-related

["Stefan /*St0fF*/ Hübner" <stefan.huebner@stud.tu-ilmenau.de>]

Neil Brown schrieb:
> On Sun, 07 Feb 2010 14:38:18 +0100
> [...]
> mdadm only checks the superblock at the start of the device to see if it
> looks like an ext3 filesystem.  So if an md array has a valid filesystem,
> then it is very likely that at least one of the devices in the array will
> appear to have a valid filesystem to mdadm.

Indeed that makes perfect sense.
> 
>[...]
> 
> Maybe there was meant to be another layer between the md array and the
> filesystem - maybe LVM ??  If there should have been an LVM and wasn't the
> filesystem would definitely look very corrupt even though the superblock
> might appear to be in the right place.
> 

Well, there's no need to tell me - the guys in taiwan just don't do it
on their NAS Devices.  But thanks for the hint.  I recall that the
successful data-recoveries were on a Thecus N5200, which does indeed use
lvm (to separate iSCSI-space, userspace, config-space, etc.)

> 
> NeilBrown
> 
Bottom-line: the customer's RAIDs were just f**ked, they should have had
taken drive-health more seriously... And the Vendor's code should get
"normalized" so that FS-checking in regular intervals takes place...

Thanks for the help,
Stefan Hübner
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