[Gluster-users] Sharding problem - multiple shard copies with mismatching gfids

Mon Mar 26 07:25:59 UTC 2018

On Mon, Mar 26, 2018 at 12:40 PM, Krutika Dhananjay <kdhananj at redhat.com>
wrote:

> The gfid mismatch here is between the shard and its "link-to" file, the
> creation of which happens at a layer below that of shard translator on the
> stack.
>
> Adding DHT devs to take a look.
>

Thanks Krutika. I assume shard doesn't do any dentry operations like
rename, link, unlink on the path of file (not the gfid handle based path)
internally while managing shards. Can you confirm? If it does these
operations, what fops does it do?

@Ian,

I can suggest following way to fix the problem:
* Since one of files listed is a DHT linkto file, I am assuming there is
only one shard of the file. If not, please list out gfids of other shards
and don't proceed with healing procedure.
* If gfids of all shards happen to be same and only linkto has a different
gfid, please proceed to step 3. Otherwise abort the healing procedure.
* If cluster.lookup-optimize is set to true abort the healing procedure
* Delete the linkto file - the file with permissions -------T and xattr
trusted.dht.linkto and do a lookup on the file from mount point after
turning off readdriplus [1].

As to reasons on how we ended up in this situation, Can you explain me what
is the I/O pattern on this file - like are there lots of entry operations
like rename, link, unlink etc on the file? There have been known races in
rename/lookup-heal-creating-linkto where linkto and data file have
different gfids. [2] fixes some of these cases

[1] http://lists.gluster.org/pipermail/gluster-users/2017-March/030148.html
[2] https://review.gluster.org/#/c/19547/

regards,
Raghavendra

>
>
>> -Krutika
>
> On Mon, Mar 26, 2018 at 1:09 AM, Ian Halliday <ihalliday at ndevix.com>
> wrote:
>
>> Hello all,
>>
>> We are having a rather interesting problem with one of our VM storage
>> systems. The GlusterFS client is throwing errors relating to GFID
>> mismatches. We traced this down to multiple shards being present on the
>> gluster nodes, with different gfids.
>>
>> Hypervisor gluster mount log:
>>
>> [2018-03-25 18:54:19.261733] E [MSGID: 133010]
>> [shard.c:1724:shard_common_lookup_shards_cbk] 0-ovirt-zone1-shard:
>> Lookup on shard 7 failed. Base file gfid = 87137cac-49eb-492a-8f33-8e33470d8cb7
>> [Stale file handle]
>> The message "W [MSGID: 109009] [dht-common.c:2162:dht_lookup_linkfile_cbk]
>> 0-ovirt-zone1-dht: /.shard/87137cac-49eb-492a-8f33-8e33470d8cb7.7: gfid
>> different on data file on ovirt-zone1-replicate-3, gfid local =
>> 00000000-0000-0000-0000-000000000000, gfid node =
>> 57c6fcdf-52bb-4f7a-aea4-02f0dc81ff56 " repeated 2 times between
>> [2018-03-25 18:54:19.253748] and [2018-03-25 18:54:19.263576]
>> [2018-03-25 18:54:19.264349] W [MSGID: 109009]
>> [dht-common.c:1901:dht_lookup_everywhere_cbk] 0-ovirt-zone1-dht:
>> /.shard/87137cac-49eb-492a-8f33-8e33470d8cb7.7: gfid differs on
>> subvolume ovirt-zone1-replicate-3, gfid local =
>> fdf0813b-718a-4616-a51b-6999ebba9ec3, gfid node =
>> 57c6fcdf-52bb-4f7a-aea4-02f0dc81ff56
>>
>>
>> On the storage nodes, we found this:
>>
>> [root at n1 gluster]# find -name 87137cac-49eb-492a-8f33-8e33470d8cb7.7
>> ./brick2/brick/.shard/87137cac-49eb-492a-8f33-8e33470d8cb7.7
>> ./brick4/brick/.shard/87137cac-49eb-492a-8f33-8e33470d8cb7.7
>>
>> [root at n1 gluster]# ls -lh ./brick2/brick/.shard/87137cac
>> -49eb-492a-8f33-8e33470d8cb7.7
>> ---------T. 2 root root 0 Mar 25 13:55 ./brick2/brick/.shard/87137cac
>> -49eb-492a-8f33-8e33470d8cb7.7
>> [root at n1 gluster]# ls -lh ./brick4/brick/.shard/87137cac
>> -49eb-492a-8f33-8e33470d8cb7.7
>> -rw-rw----. 2 root root 3.8G Mar 25 13:55 ./brick4/brick/.shard/87137cac
>> -49eb-492a-8f33-8e33470d8cb7.7
>>
>> [root at n1 gluster]# getfattr -d -m . -e hex ./brick2/brick/.shard/87137cac
>> -49eb-492a-8f33-8e33470d8cb7.7
>> # file: brick2/brick/.shard/87137cac-49eb-492a-8f33-8e33470d8cb7.7
>> security.selinux=0x73797374656d5f753a6f626a6563745f723a756e6
>> c6162656c65645f743a733000
>> trusted.gfid=0xfdf0813b718a4616a51b6999ebba9ec3
>> trusted.glusterfs.dht.linkto=0x6f766972742d3335302d7a6f6e653
>> 12d7265706c69636174652d3300
>>
>> [root at n1 gluster]# getfattr -d -m . -e hex ./brick4/brick/.shard/87137cac
>> -49eb-492a-8f33-8e33470d8cb7.7
>> # file: brick4/brick/.shard/87137cac-49eb-492a-8f33-8e33470d8cb7.7
>> security.selinux=0x73797374656d5f753a6f626a6563745f723a756e6
>> c6162656c65645f743a733000
>> trusted.afr.dirty=0x000000000000000000000000
>> trusted.bit-rot.version=0x020000000000000059914190000ce672
>> trusted.gfid=0x57c6fcdf52bb4f7aaea402f0dc81ff56
>>
>>
>> I'm wondering how they got created in the first place, and if anyone has
>> any insight on how to fix it?
>>
>> Storage nodes:
>> [root at n1 gluster]# gluster --version
>> glusterfs 4.0.0
>>
>> [root at n1 gluster]# gluster volume info
>>
>> Volume Name: ovirt-350-zone1
>> Type: Distributed-Replicate
>> Volume ID: 106738ed-9951-4270-822e-63c9bcd0a20e
>> Status: Started
>> Snapshot Count: 0
>> Number of Bricks: 7 x (2 + 1) = 21
>> Transport-type: tcp
>> Bricks:
>> Brick1: 10.0.6.100:/gluster/brick1/brick
>> Brick2: 10.0.6.101:/gluster/brick1/brick
>> Brick3: 10.0.6.102:/gluster/arbrick1/brick (arbiter)
>> Brick4: 10.0.6.100:/gluster/brick2/brick
>> Brick5: 10.0.6.101:/gluster/brick2/brick
>> Brick6: 10.0.6.102:/gluster/arbrick2/brick (arbiter)
>> Brick7: 10.0.6.100:/gluster/brick3/brick
>> Brick8: 10.0.6.101:/gluster/brick3/brick
>> Brick9: 10.0.6.102:/gluster/arbrick3/brick (arbiter)
>> Brick10: 10.0.6.100:/gluster/brick4/brick
>> Brick11: 10.0.6.101:/gluster/brick4/brick
>> Brick12: 10.0.6.102:/gluster/arbrick4/brick (arbiter)
>> Brick13: 10.0.6.100:/gluster/brick5/brick
>> Brick14: 10.0.6.101:/gluster/brick5/brick
>> Brick15: 10.0.6.102:/gluster/arbrick5/brick (arbiter)
>> Brick16: 10.0.6.100:/gluster/brick6/brick
>> Brick17: 10.0.6.101:/gluster/brick6/brick
>> Brick18: 10.0.6.102:/gluster/arbrick6/brick (arbiter)
>> Brick19: 10.0.6.100:/gluster/brick7/brick
>> Brick20: 10.0.6.101:/gluster/brick7/brick
>> Brick21: 10.0.6.102:/gluster/arbrick7/brick (arbiter)
>> Options Reconfigured:
>> cluster.min-free-disk: 50GB
>> performance.strict-write-ordering: off
>> performance.strict-o-direct: off
>> nfs.disable: off
>> performance.readdir-ahead: on
>> transport.address-family: inet
>> performance.cache-size: 1GB
>> features.shard: on
>> features.shard-block-size: 5GB
>> server.event-threads: 8
>> server.outstanding-rpc-limit: 128
>> storage.owner-uid: 36
>> storage.owner-gid: 36
>> performance.quick-read: off
>> performance.read-ahead: off
>> performance.io-cache: off
>> performance.stat-prefetch: on
>> cluster.eager-lock: enable
>> network.remote-dio: enable
>> cluster.quorum-type: auto
>> cluster.server-quorum-type: server
>> cluster.data-self-heal-algorithm: full
>> performance.flush-behind: off
>> performance.write-behind-window-size: 8MB
>> client.event-threads: 8
>> server.allow-insecure: on
>>
>>
>> Client version:
>> [root at kvm573 ~]# gluster --version
>> glusterfs 3.12.5
>>
>>
>> Thanks!
>>
>> - Ian
>>
>>
>> _______________________________________________
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>> Gluster-users at gluster.org
>> http://lists.gluster.org/mailman/listinfo/gluster-users
>>
>
>
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