The answer came offline, and I guess I never replied back to the
original posting. This is what I learned. It deals with only a single
file, not 1000's. --bob
-------------------------------
On Mon, 14 Mar 2016, Bob Ball wrote:
OK, it would seem the affected user has already deleted this file, as
the "lfs fid2path" returns:
[root@umt3int01 ~]# lfs fid2path /lustre/umt3 [0x200002582:0xb5c0:0x0]
fid2path: error on FID [0x200002582:0xb5c0:0x0]: No such file or directory
I verified I could to it back and forth using a different file.
I am making one last check, with the OST re-activated (I had set it
inactive on our MDT/MGS to keep new files off while figuring this out).
Nope, gone. Time to do the clear and remove the snapshot.
Thanks for your help on this.
bob
On 3/14/2016 10:45 AM, Don Holmgren wrote:
No, no downside. The snapshot really is just used so that I can do this
sort of repair live.
Once you've found the Lustre OID with "find", for ll_decode_filter_fid to
work you'll have to then umount the OST and remount as type lustre.
Good luck!
Don
Thank you! This is very helpful.
I have no space to make a snapshot, so I will just umount this OST for a
bit and remount it zfs. Our users can take some off-time if we are not
busy just then.
It will be an interesting process. I'm all set to drain and remake
though, should this method not work. I was putting that off to start
until later today as I've other issues just now. Since it would take me
2-3 days total to drain, remake and refill, your detailed method is far
more likeable for me.
Just to be certain, other than the temporary unavailability of the
Lustre file system, do you see any downside to not working from a snapshot?
bob
On 3/14/2016 10:21 AM, Don Holmgren wrote:
Hi Bob -
I only get the lustre-discuss digest, so am not sure how to reply to that
whole list. But I can reply directly to you regarding your posting
(copied at the bottom).
In the ZFS error message
errors: Permanent errors have been detected in the following files:
ost-007/ost0030:<0x2c90f>
0x2c90f is the ZFS inode number of the damaged item. To turn this into a
Lustre filename, do the following:
1. First, you have to use "find" using that inode number to get the
corresponding
Lustre object ID. I do this via a ZFS snapshot, something like:
zfs snapshot ost-007/ost0030@mar14
mount -t zfs ost-007/ost0030@mar14 /mnt/snapshot
find /mnt/snapshot/O -inum 182543
(note 0x2c90f = 182543 decimal). This may return something like
/mnt/snapshot/O/0/d22/54
if indeed the damaged item is a file object.
2. OK, assuming the "find" did return a file object like above (in this
case the
Lustre OID of the object is 54) you need to find the parent "FID" of
that
OID. Do this as follows on the OSS where you've mounted the snapshot:
[root@lustrenew3 ~]# ll_decode_filter_fid /mnt/snapshot/O/0/d22/54
/mnt/snapshot/O/0/d22/54: parent=[0x20000040000010a:0x0:0x0] stripe=0
3. That string "0x20000040000010a:0x0:0x0" is related to the Lustre FID.
You
can use "lfs fid2path" to convert this to a filename. "lfs fid2path"
must be
execute on a client of your Lustre filesystem. And, on our Lustre,
the
return string must be slightly altered (chopped up differently):
[root@client ~]# lfs fid2path /djhzlus [0x200000400:0x10a:0x0]
/djhzlus/test/copy1/l6496f21b7075m00155m031/gauge/Coulomb/l6496f21b7075m00155m031-Coul_002
Here /djhzlus was where the Lustre filesystem was mounted on my client
(client). fid2path takes three numbers, in my case the first was
the first 9 hex digits of the return from ll_decode_filter_fid, and
the
second was the last 5 hex digits (I supressed the leading zeros) and
the
third was 0x0 (not sure whether this was the 2nd or 3rd field from
ll_decode_filter_fid.
You can always use "lfs path2fid" on your Lustre client against
another
file in your filesystem to find the pattern for your FID.
To check that you've indeed found the correct file, you can do
"lfs getstripe" to confirm that the objid matches the Lustre OID you
got with the find.
Once you figure out the bad file, you can delete it from Lustre, and then
use "zpool clear ost-007" to clear the reporting of
ost-007/ost0030:<0x2c90f>
Don't forget to umount and delete your ZFS snapshot of the OST with the
bad file.
I should mention that I found a Python script ("zfsobj2fid") somewhere
that directly returns the FID using the ZFS debugger ("zdb") directly
against the mounted OST. You can probably google for zfsobj2fid; if you
can't find it let me know and I'll dig around to see if I still have a
copy. Here's how I used it to get the FID for "lfs fid2path":
[root@lustrenew3 ~]# ./zfsobj2fid zp2/ost2 0x113
[0x20000040000010a:0x0:0x0]
(my OID was 0x113, my pool was "zp2" and the ZFS OST was "ost2"). But,
note that the FID returned still needs to be manipulated as above. I
found this note in one of my write-ups about this manipulation:
"Evidentally, the 'trusted.fid' xattr kept in ZFS for the OID file
contains both the first and second sections of the FID (according to some
slide decks I found, the FID is [sequence:objectID:version], so the xattr
has the sequence and the objectID."
Cheers -
Don Holmgren
Fermilab
On 7/12/2016 12:02 AM, Kevin Abbey wrote:
Hi,
Can anyone advise how to clean up 1000s of zfs level permanent errors
and the lustre level too?
A similar question was presented on the list but I did not see an answer.
https://www.mail-archive.com/lustre-discuss@lists.lustre.org/msg12454.html
As I was testing new hardware I discovered an LSI HBA was bad. On a
single combined MDS/OSS there were 8 OSTs split across 2 jbod and 2
LSI HBA. The mdt was on a 3rd jbod downlinked on the jbod connected
with the bad controller. The zpools connected to the good HBA were
scrubed clean after unmounting and stopping lustre. The zpools on the
bad controller continued to have errors while connected to the bad
controller. One of these OSTs reported a disk failure during the
scrub and began resilvering yet autoreplace was off. This is a very
bad event considering the card was causing all of the errors. Neither
a scrub or resilver would ever complete. I stopped the scrub on the 3
other osts and detached the spare from the ost in resilver process.
After narrowing down the bad HBA (initially it was not clear if cables
or jbod backplanes were bad), I use the good HBA to scrub the jbod 1
again, then shutdown disconnected the jbod1. Then proceeded to
connect the jbod2 to the good controller to scrub the jbod 2 zpools
which had previously been attached to the bad LSI controller. The 3
zpools which had scrub stopped previously did complete successfully.
The one which had begun resilvering began again to resilver after I
initiated a replace of the failed disk with the spare. The resilver
completed but many permanent errors were discovered on the zpool.
Since this is a test pool I was interested to know if zfs would
recover. In a real scenario with HW problems I'll shutdown and
disconnect the data drives prior to HW testing.
The status listed below shows a new scrub in process after the
resilver completed. The cache drive is missing because the 3rd jbod
is disconnected temporarily.
===================================
ZFS: v0.6.5.7-1
lustre 2.8.55
kernel 2.6.32_642.1.1.el6.x86_64.x86_64
Centos 6.8
===================================
~]# zpool status -v test-ost4
pool: test-ost4
state: ONLINE
status: One or more devices has experienced an error resulting in data
corruption. Applications may be affected.
action: Restore the file in question if possible. Otherwise restore the
entire pool from backup.
see: http://zfsonlinux.org/msg/ZFS-8000-8A
scan: scrub in progress since Mon Jul 11 22:29:09 2016
689G scanned out of 12.4T at 711M/s, 4h49m to go
40K repaired, 5.41% done
config:
NAME STATE READ WRITE CKSUM
test-ost4 ONLINE 0 0 180
raidz2-0 ONLINE 0 0 360
ata-ST4000NM0033-9ZM170_Z1Z7GYXY ONLINE 0 0 2
(repairing)
ata-ST4000NM0033-9ZM170_Z1Z7KKPQ ONLINE 0 0 3
(repairing)
ata-ST4000NM0033-9ZM170_Z1Z7L5E7 ONLINE 0 0 3
(repairing)
ata-ST4000NM0033-9ZM170_Z1Z7KGQT ONLINE 0 0 0
(repairing)
ata-ST4000NM0033-9ZM170_Z1Z7LA8K ONLINE 0 0 4
(repairing)
ata-ST4000NM0033-9ZM170_Z1Z7KB0X ONLINE 0 0 3
(repairing)
ata-ST4000NM0033-9ZM170_Z1Z7JSMN ONLINE 0 0 2
(repairing)
ata-ST4000NM0033-9ZM170_Z1Z7KXRA ONLINE 0 0 2
(repairing)
ata-ST4000NM0033-9ZM170_Z1Z7MLSN ONLINE 0 0 2
(repairing)
ata-ST4000NM0033-9ZM170_Z1Z7L4DT ONLINE 0 0 7
(repairing)
cache
ata-D2CSTK251M20-0240_A19CV011227000092 UNAVAIL 0 0 0
errors: Permanent errors have been detected in the following files:
test-ost4/test-ost4:<0xe00>
test-ost4/test-ost4:<0xe01>
test-ost4/test-ost4:<0xe02>
test-ost4/test-ost4:<0xe03>
test-ost4/test-ost4:<0xe04>
test-ost4/test-ost4:<0xe05>
test-ost4/test-ost4:<0xe06>.......
.......
.......continues......
.......
.......
test-ost4/test-ost4:<0xdfe>
test-ost4/test-ost4:<0xdff>
===================================
Follow up questions,
Is is better to not have a spare attached to the pool to prevent
resilvering in this scenario? (bad HBA, disk failed during scrub,
resilver began, yet auto relplace was off. The spare was assigned to
the zpool.)
In a dual path to the jbod would the bad HBA card be disabled
automatically to prevent IO errors reaching the disk? The current
setup is single path only.
Thank you for any notes in advance,
Kevin
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