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"Ghost" static volume appeared, how to remove it.

Posted: Fri Jul 12, 2019 2:07 am
by eguitton
Hi,

first of all forgive my poor english, French native speaker here.

We manage 2 NAS in a customer's site, one's out of this story, the other QNAP concerning this post is used for backups.

It's a TS-451+ model, current version is 4.3.6.0993

background story :
After having lost a disk and then failed during raid reconstruction (another disk got an error), the raid has been locked in read-only mode (thank you qnap for that, we could copy all the critical data !)
At that point, 2 HDD in error, I knew I had to redo it all from scratch, and we proposed our customer to change all disk (3To) by larger ones (6To) so we could solve his lack of space problem (the scope of the backups to do has enlarged due to an unstable other job used to backup data on magnetic bands, long story short : this other backup is unplanned and added to te NAS with veeam).

So... I changed all the HDD in the same time -> loss of config, that's ok.
Redo all the config (new pool storage with a thick volume within (previous was a static volume, which i didn't like because couldn't handle snapshots, that was two birds with a rock)), recreated all rights and shares, move the data back in where expected, and restarted the backup jobs : all ok, yeah !

Few weeks later :
Our customer enterprise had an thunderstorm 2 nights ago, and despite being secured by an UPS, both NAS had a power outage.

Now our Backup NAS is still working fine, but... it looks like the old static volume has reappeared in addition to the new one !
It's listed as unmounted, and I can't manage it (I want to delete it, it can't exist when the pool already uses 16 To, there can't be room for that 8To static volume) because the web interface just hangs on it.
I can close the panel, but I can't delete it, and capacity estimation just hangs without displaying any data, just the animation.

Now when i check the raid it's still OK, but since the web interface seems to fail, how can I list all volumes to detect this ghost volume (which is out of the pool storage, see image 1), and more importantly how can I delete it in cli mode ?

few pics in attachement : 1-2-3 is the web ui, 4-5 a quick ssh check.

thank you for your time, I tried to search through all the "unmounted volume" posts on the forum, but none seems to fit my need, or I missed/didn't understood it clearly. (most post explain how to check and repair, I simply want to delete this static one wuthout touching a bit of the existing real volume which is actually healthy and functionnal).

Sincerely,

E.Guitton

Re: "Ghost" static volume appeared, how to remove it.

Posted: Fri Jul 12, 2019 2:10 am
by eguitton
don't know why, but with pics it said "detected as spam"
trying to put them here

Re: "Ghost" static volume appeared, how to remove it.

Posted: Fri Jul 12, 2019 3:50 pm
by storageman
Can you launch "/etc/init.d/init_lvm.sh" and report what happens.

Re: "Ghost" static volume appeared, how to remove it.

Posted: Sat Jul 13, 2019 12:51 am
by eguitton
[~] # /etc/init.d/init_lvm.sh
Changing old config name...
Reinitialing...
Detect disk(8, 0)...
dev_count ++ = 0Detect disk(8, 16)...
dev_count ++ = 1Detect disk(8, 32)...
dev_count ++ = 2Detect disk(8, 48)...
dev_count ++ = 3Detect disk(8, 64)...
ignore non-root enclosure disk(8, 64).
Detect disk(8, 0)...
Detect disk(8, 16)...
Detect disk(8, 32)...
Detect disk(8, 48)...
Detect disk(8, 64)...
ignore non-root enclosure disk(8, 64).
sys_startup_p2:got called count = -1
Found duplicate PV EJTZ9X4qarN4bT94drG6Az7Md8sJnRKJ: using /dev/drbd1 not /dev/md1
Using duplicate PV /dev/drbd1 from subsystem DRBD, ignoring /dev/md1
sh: /sys/block/dm-6/dm/pool/tier/relocation_rate: Permission denied
Done

And... now everything's back to normal, no more additionnal unwanted volume !
Thanks a lot, I love you :)

Just for reference, what's the purpose of that internal script ?

Re: "Ghost" static volume appeared, how to remove it.

Posted: Mon Jul 15, 2019 4:22 pm
by storageman
It relaunches the logical volume manager and re-reads settings from the storage config.

Seems yours got it knickers in a twist!

Re: "Ghost" static volume appeared, how to remove it.

Posted: Tue Jul 16, 2019 5:12 am
by eguitton
indeed. thanks for your help and explanations !

Re: "Ghost" static volume appeared, how to remove it.

Posted: Tue Nov 03, 2020 4:43 pm
by masuc
Thank you Storageman,

I had the same annoying issue and your magic trick worked for me as well