[Lustre-discuss] how do I deactivate a very wonky OST

[Sean Brisbane]

You shouldn’t need the OST to be working to find the files if you can mount the file-system without the OST.  There is enough information on the MDT.

I have seen times when for some OSTs lfs find does not work unless you use the OST index instead of the name as the argument:

i.e

lfs find -ost atlas25-OST00de

does not work but

lfs find -ost {index}

where {index}is worked out from the output of lfs df, and is '222' in the example below.

atlas25-OST00de_UUID 19494707336 17711886956   807775824  96% /lustre/atlas25[OST:222]

Cheers,
Sean



________________________________
From: Andrus, Brian Contractor [bdandrus at nps.edu]
Sent: 14 January 2015 23:11
To: Sean Brisbane; lustre-discuss at lists.lustre.org
Subject: RE: how do I deactivate a very wonky OST

Thanks Sean,

Right now neither help me as I had to bring the entire system up from scratch and NOT mount the bad OST.
So, now OST5 is not listed anywhere. The only knows it is missing.
Doing ‘lctl dl’ only show the OSTs that have been brought up.
If I try to bring it up, it registers, the MDS becomes aware, the OSS kernel panics and the MDS starts making everyone wait for it to come back.

Part of ‘lfs df’:
OST0005             : Resource temporarily unavailable

Hassle is I cannot really do an ‘lfs find’ for the files on the bad OST because the OST is not registered… stuck in a loop here…

If I could find a way to tag it as offline even though the MDS doesn’t see it yet, that may help.


Brian Andrus
ITACS/Research Computing
Naval Postgraduate School
Monterey, California
voice: 831-656-6238




From: Sean Brisbane [mailto:s.brisbane1 at physics.ox.ac.uk]
Sent: Wednesday, January 14, 2015 3:04 PM
To: Andrus, Brian Contractor; lustre-discuss at lists.lustre.org
Subject: RE: how do I deactivate a very wonky OST

This caught me out in a recent upgrade:

cat /proc/fs/lustre/lov/{yourmdt}/target_obd

rather than

"lctl dl"

Shows the state of the OST.

Cheers,
Sean
________________________________
From: lustre-discuss-bounces at lists.lustre.org<mailto:lustre-discuss-bounces at lists.lustre.org> [lustre-discuss-bounces at lists.lustre.org] on behalf of Andrus, Brian Contractor [bdandrus at nps.edu]
Sent: 13 January 2015 17:28
To: lustre-discuss at lists.lustre.org<mailto:lustre-discuss at lists.lustre.org>
Subject: [Lustre-discuss] how do I deactivate a very wonky OST
All,

We are still trying to move forward getting our filesystem at least partially up with a failed OST.

Currently the OST will kernel panic any device that mounts it. That seems to be a constant.

So, the plan is to bring the system up without that OST and find what data will be lost.
Now, I am trying to deactivate the OST on the MGS, but it seems to have no effect.
Running lctl --device 14 deactivate does not change anything. The OST still shows ‘UP’

Is there a way to force lustre to deactivate an OST altogether when it is showing ‘UP’ and the OST is not going to be happily mounted?

I can mount the filesystem, but many actions hang (ls, df, etc).

Brian Andrus
ITACS/Research Computing
Naval Postgraduate School
Monterey, California
voice: 831-656-6238

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