UFS How to access data from degraded mirror?

cpcnw

cpcnw

Hi All,

Is it possible to still access the data from a degraded geom mirror following one disc carking it?

Currently I don't have another disc to add back in but would like to access the data if possible?

# gmirror status
Name Status Components
mirror/RAID1 DEGRADED ada1 (ACTIVE)

I'm assuming its ada0 that's the disc that died. Is there anything I can do to get at the data?

Thanks a mill!
 
Mirrors are "data is duplicated". So writes to the mirror, even in degraded mode should complete correctly on one of the devices. So data is complete on the non-degraded member. You should be able to replace the bad member, bring it into the mirror, the mirror resilvers and then both devices have the data.
 
I know what I *should* do - but I don't have a second disc currently and want to access the data. Is it possible to take that disc out of the RAID and access it via UFS?
 
cpcnw said:
I know what I *should* do - but I don't have a second disc currently and want to access the data. Is it possible to take that disc out of the RAID and access it via UFS?
Click to expand...
You should be able to access it without doing any changes. Mirror reads typically "complete from either device".

I'm not sure of the geom commands, but you should be able to remove the failed member from the mirror to just make it easier.
 
# mount /dev/ufsid/53206bf99f3aa074 /mnt/data
mount: /dev/ufsid/53206bf99f3aa074: R/W mount of /mnt/data denied. Filesystem is not clean - run fsck.
Forced mount will invalidate journal contents: Operation not permitted
 
I don't know the correct commands but I would think about a geom command to break the mirror. Then maybe that lets you force mount the remaining member.

Again, I'm speculating because I've never set up a geom mirror
 
just fsck -fy it and you will be able to mount it rw
or mount it ro / that should work even without fack
 
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