[Gluster-users] Geo-Replication - Changelog socket is not present - Falling back to xsync

PEPONNET, Cyril N (Cyril) cyril.peponnet at alcatel-lucent.com
Wed May 27 15:58:00 UTC 2015 

Hi and thanks again for those explanation.

Due to lot of missing files and not up to date (with gfid mismatch some time), I reset the index (or I think I do) by:

deleting the geo-reop, reset geo-replication.indexing (set it to off does not work for me), and recreate it again.

So for now it’s still in hybrid crawl process.

I end up with that because some entire folder where not synced up by the first hybrid crawl (and touch does nothing afterward in changelog). In fact touch anyfile doesnt trigger any resync, only delete/rename/change do.

1/
>  1. Directories:
>      #setfattr -n glusterfs.geo-rep.trigger-sync -v "1" <DIR>
>  2. Files:
>      #setfattr -n glusterfs.geo-rep.trigger-sync -v “1" <file-path>

Is is recursive ? (for directories) or I have to do that on each mismatching files ? Should I do that on master or slave ?

2/ For the RO I can pass the Option: nfs.volume-access to read-only, this will pass the vol in RO for nfs mount and glusterfs mount. Correct ?

Thank you so much for your help.
-- 
Cyril Peponnet

> On May 26, 2015, at 11:29 PM, Kotresh Hiremath Ravishankar <khiremat at redhat.com> wrote:
> 
> Hi Cyril,
> 
> Need some clarifications. Comments inline.
> 
> Thanks and Regards,
> Kotresh H R
> 
> ----- Original Message -----
>> From: "Cyril N PEPONNET (Cyril)" <cyril.peponnet at alcatel-lucent.com>
>> To: "Kotresh Hiremath Ravishankar" <khiremat at redhat.com>
>> Cc: "gluster-users" <gluster-users at gluster.org>
>> Sent: Tuesday, May 26, 2015 11:43:44 PM
>> Subject: Re: [Gluster-users] Geo-Replication - Changelog socket is not present - Falling back to xsync
>> 
>> So, changelog is still active but I notice that some file were missing.
>> 
>> So I ‘m running a rsync -avn between the two vol (master and slave) to sync
>> then again by touching the missing files (hopping geo-rep will do the rest).
>> 
>  Are you running rsync -avn for missed files between master and slave volumes ?
>  If yes, that is dangerous and it should not be done. Geo-replication demands gfid
>  of files between master and slave to be intact (meaning the gfid of 'file1' in
>  master vol should be same as 'file1' in slave). It is required because, the data sync
>  happens using 'gfid' not the 'pathname' of the file. So if manual rsync is used
>  to sync files between master and slave using pathname, gfids will change and
>  further syncing on those files fails through geo-rep.
> 
>  A virtual setxattr interface is provided to sync missing files through geo-replication.
>  It makes sure gfids are intact. 
> 
>  NOTE: Directories have to be synced to slave before trying setxattr for files inside it.
> 
>  1. Directories:
>      #setfattr -n glusterfs.geo-rep.trigger-sync -v "1" <DIR>
>  2. Files:
>      #setfattr -n glusterfs.geo-rep.trigger-sync -v "1" <file-path>
> 
>> One question, can I pass the slave vol a RO ? Because if somebody change a
>> file in the slave it’s no longer synced (changes and delete but rename keep
>> synced between master and slave).
>> 
>> Will it have an impact on geo-replication process if I pass the slave vol a
>> RO ?
> 
>  Again if slave volume is modified by something else other than geo-rep, we might
>  end up in mismatch of gfids. So exposing the slave volume to consumers as RO is always
>  a good idea. It doesn't affect geo-rep as it internally mounts in RW.
> 
>  Hope this helps. Let us know if anything else. We are happy to help you.
>> 
>> Thanks again.
>> 
>> 
>> --
>> Cyril Peponnet
>> 
>> On May 25, 2015, at 12:43 AM, Kotresh Hiremath Ravishankar
>> <khiremat at redhat.com<mailto:khiremat at redhat.com>> wrote:
>> 
>> Hi Cyril,
>> 
>> Answers inline
>> 
>> Thanks and Regards,
>> Kotresh H R
>> 
>> ----- Original Message -----
>> From: "Cyril N PEPONNET (Cyril)"
>> <cyril.peponnet at alcatel-lucent.com<mailto:cyril.peponnet at alcatel-lucent.com>>
>> To: "Kotresh Hiremath Ravishankar"
>> <khiremat at redhat.com<mailto:khiremat at redhat.com>>
>> Cc: "gluster-users"
>> <gluster-users at gluster.org<mailto:gluster-users at gluster.org>>
>> Sent: Friday, May 22, 2015 9:34:47 PM
>> Subject: Re: [Gluster-users] Geo-Replication - Changelog socket is not
>> present - Falling back to xsync
>> 
>> One last question, correct me if I’m wrong.
>> 
>> When you start a geo-rep process it starts with xsync aka hybrid crawling
>> (sending files every 60s, with files windows set as 8192 files per sent).
>> 
>> When the crawl is done it should use changelog detector and dynamically
>> change things to slaves.
>> 
>> 1/ During the hybride crawl, if we delete files from master (and they were
>> already transfered to the slave), xsync process will not delete them from
>> the slave (and we can’t change as the option as is hardcoded).
>> When it will pass to changelog, will it remove the non existent folders and
>> files on the slave that are no longer on the master ?
>> 
>> 
>> You are right, xsync does not sync delete files, once it is already synced.
>> After xsync, when it switches to changelog, it doesn't delete all the non
>> existing
>> entries on slave that are no longer on the master. Changelog is capable of
>> deleting
>> files from the time it got switched to changelog.
>> 
>> 2/ With changelog, if I add a file of 10GB and after a file of 1KB, will the
>> changelog process with queue (waiting for the 10GB file to be sent) or are
>> the sent done in thread ?
>> (ex I add a 10GB file and I delete it after 1min, what will happen ?)
>> 
>>  Changelog records the operations happened in master and is replayed by
>>  geo-replication
>>  on to slave volume. Geo-replication syncs files in two phases.
>> 
>>  1. Phase-1: Create entries through RPC( 0 byte files on slave keeping gfid
>>  intact as in master)
>>  2. Phase-2: Sync data, through rsync/tar_over_ssh (Multi threaded)
>> 
>>  Ok, now keeping that in mind, Phase-1 happens serially, and the phase two
>>  happens parallely.
>>  Zero byte files of 10GB and 1KB gets created on slave serially and data for
>>  the same syncs
>>  parallely. Another thing to remember, geo-rep makes sure that, syncing data
>>  to file is tried
>>  only after zero byte file for the same is created already.
>> 
>> 
>> In latest release 3.7, xsync crawl is minimized by the feature called history
>> crawl introduced in 3.6.
>> So the chances of missing deletes/renames are less.
>> 
>> Thanks.
>> 
>> --
>> Cyril Peponnet
>> 
>> On May 21, 2015, at 10:22 PM, Kotresh Hiremath Ravishankar
>> <khiremat at redhat.com<mailto:khiremat at redhat.com>> wrote:
>> 
>> Great, hope that should work. Let's see
>> 
>> Thanks and Regards,
>> Kotresh H R
>> 
>> ----- Original Message -----
>> From: "Cyril N PEPONNET (Cyril)"
>> <cyril.peponnet at alcatel-lucent.com<mailto:cyril.peponnet at alcatel-lucent.com>>
>> To: "Kotresh Hiremath Ravishankar"
>> <khiremat at redhat.com<mailto:khiremat at redhat.com>>
>> Cc: "gluster-users"
>> <gluster-users at gluster.org<mailto:gluster-users at gluster.org>>
>> Sent: Friday, May 22, 2015 5:31:13 AM
>> Subject: Re: [Gluster-users] Geo-Replication - Changelog socket is not
>> present - Falling back to xsync
>> 
>> Thanks to JoeJulian / Kaushal I managed to re-enable the changelog option
>> and
>> the socket is now present.
>> 
>> For the record I had some clients running rhs gluster-fuse and our nodes
>> are
>> running glusterfs release and op-version are not “compatible”.
>> 
>> Now I have to wait for the init crawl see if it switches to changelog
>> detector mode.
>> 
>> Thanks Kotresh
>> --
>> Cyril Peponnet
>> 
>> On May 21, 2015, at 8:39 AM, Cyril Peponnet
>> <cyril.peponnet at alcatel-lucent.com<mailto:cyril.peponnet at alcatel-lucent.com>>
>> wrote:
>> 
>> Hi,
>> 
>> Unfortunately,
>> 
>> # gluster vol set usr_global changelog.changelog off
>> volume set: failed: Staging failed on
>> mvdcgluster01.us.alcatel-lucent.com<http://mvdcgluster01.us.alcatel-lucent.com>.
>> Error: One or more connected clients cannot support the feature being
>> set.
>> These clients need to be upgraded or disconnected before running this
>> command again
>> 
>> 
>> I don’t know really why, I have some clients using 3.6 as fuse client
>> others are running on 3.5.2.
>> 
>> Any advice ?
>> 
>> --
>> Cyril Peponnet
>> 
>> On May 20, 2015, at 5:17 AM, Kotresh Hiremath Ravishankar
>> <khiremat at redhat.com<mailto:khiremat at redhat.com>> wrote:
>> 
>> Hi Cyril,
>> 
>> From the brick logs, it seems the changelog-notifier thread has got
>> killed
>> for some reason,
>> as notify is failing with EPIPE.
>> 
>> Try the following. It should probably help:
>> 1. Stop geo-replication.
>> 2. Disable changelog: gluster vol set <master-vol-name>
>> changelog.changelog off
>> 3. Enable changelog: glluster vol set <master-vol-name>
>> changelog.changelog on
>> 4. Start geo-replication.
>> 
>> Let me know if it works.
>> 
>> Thanks and Regards,
>> Kotresh H R
>> 
>> ----- Original Message -----
>> From: "Cyril N PEPONNET (Cyril)"
>> <cyril.peponnet at alcatel-lucent.com<mailto:cyril.peponnet at alcatel-lucent.com>>
>> To: "gluster-users"
>> <gluster-users at gluster.org<mailto:gluster-users at gluster.org>>
>> Sent: Tuesday, May 19, 2015 3:16:22 AM
>> Subject: [Gluster-users] Geo-Replication - Changelog socket is not
>> present - Falling back to xsync
>> 
>> Hi Gluster Community,
>> 
>> I have a 3 nodes setup at location A and a two node setup at location
>> B.
>> 
>> All running 3.5.2 under Centos-7.
>> 
>> I have one volume I sync through georeplication process.
>> 
>> So far so good, the first step of geo-replication is done
>> (hybrid-crawl).
>> 
>> Now I’d like to use the change log detector in order to delete files on
>> the
>> slave when they are gone on master.
>> 
>> But it always fallback to xsync mecanism (even when I force it using
>> config
>> changelog_detector changelog):
>> 
>> [2015-05-18 12:29:49.543922] I [monitor(monitor):129:monitor] Monitor:
>> ------------------------------------------------------------
>> [2015-05-18 12:29:49.544018] I [monitor(monitor):130:monitor] Monitor:
>> starting gsyncd worker
>> [2015-05-18 12:29:49.614002] I [gsyncd(/export/raid/vol):532:main_i]
>> <top>:
>> syncing: gluster://localhost:vol ->
>> ssh://root@x.x.x.x:gluster://localhost:vol
>> [2015-05-18 12:29:54.696532] I
>> [master(/export/raid/vol):58:gmaster_builder]
>> <top>: setting up xsync change detection mode
>> [2015-05-18 12:29:54.696888] I [master(/export/raid/vol):357:__init__]
>> _GMaster: using 'rsync' as the sync engine
>> [2015-05-18 12:29:54.697930] I
>> [master(/export/raid/vol):58:gmaster_builder]
>> <top>: setting up changelog change detection mode
>> [2015-05-18 12:29:54.698160] I [master(/export/raid/vol):357:__init__]
>> _GMaster: using 'rsync' as the sync engine
>> [2015-05-18 12:29:54.699239] I [master(/export/raid/vol):1104:register]
>> _GMaster: xsync temp directory:
>> /var/run/gluster/vol/ssh%3A%2F%2Froot%40x.x.x.x%3Agluster%3A%2F%2F127.0.0.1%3Avol/ce749a38ba30d4171cd674ec00ab24f9/xsync
>> [2015-05-18 12:30:04.707216] I
>> [master(/export/raid/vol):682:fallback_xsync]
>> _GMaster: falling back to xsync mode
>> [2015-05-18 12:30:04.742422] I
>> [syncdutils(/export/raid/vol):192:finalize]
>> <top>: exiting.
>> [2015-05-18 12:30:05.708123] I [monitor(monitor):157:monitor] Monitor:
>> worker(/export/raid/vol) died in startup phase
>> [2015-05-18 12:30:05.708369] I [monitor(monitor):81:set_state] Monitor:
>> new
>> state: faulty
>> [201
>> 
>> After some python debugging and stack strace printing I figure out
>> that:
>> 
>> /var/run/gluster/vol/ssh%3A%2F%2Froot%40x.x.x.x%3Agluster%3A%2F%2F127.0.0.1%3Avol/ce749a38ba30d4171cd674ec00ab24f9/changes.log
>> 
>> [2015-05-18 19:41:24.511423] I
>> [gf-changelog.c:179:gf_changelog_notification_init] 0-glusterfs:
>> connecting
>> to changelog socket:
>> /var/run/gluster/changelog-ce749a38ba30d4171cd674ec00ab24f9.sock
>> (brick:
>> /export/raid/vol)
>> [2015-05-18 19:41:24.511445] W
>> [gf-changelog.c:189:gf_changelog_notification_init] 0-glusterfs:
>> connection
>> attempt 1/5...
>> [2015-05-18 19:41:26.511556] W
>> [gf-changelog.c:189:gf_changelog_notification_init] 0-glusterfs:
>> connection
>> attempt 2/5...
>> [2015-05-18 19:41:28.511670] W
>> [gf-changelog.c:189:gf_changelog_notification_init] 0-glusterfs:
>> connection
>> attempt 3/5...
>> [2015-05-18 19:41:30.511790] W
>> [gf-changelog.c:189:gf_changelog_notification_init] 0-glusterfs:
>> connection
>> attempt 4/5...
>> [2015-05-18 19:41:32.511890] W
>> [gf-changelog.c:189:gf_changelog_notification_init] 0-glusterfs:
>> connection
>> attempt 5/5...
>> [2015-05-18 19:41:34.512016] E
>> [gf-changelog.c:204:gf_changelog_notification_init] 0-glusterfs: could
>> not
>> connect to changelog socket! bailing out...
>> 
>> 
>> /var/run/gluster/changelog-ce749a38ba30d4171cd674ec00ab24f9.sock
>> doesn’t
>> exist. So the
>> https://github.com/gluster/glusterfs/blob/release-3.5/xlators/features/changelog/lib/src/gf-changelog.c#L431
>> is failing because
>> https://github.com/gluster/glusterfs/blob/release-3.5/xlators/features/changelog/lib/src/gf-changelog.c#L153
>> cannot open the socket file.
>> 
>> And I don’t find any error related to changelog in log files, except on
>> brick
>> logs node 2 (site A)
>> 
>> bricks/export-raid-vol.log-20150517:[2015-05-14 17:06:52.636908] E
>> [changelog-helpers.c:168:changelog_rollover_changelog] 0-vol-changelog:
>> Failed to send file name to notify thread (reason: Broken pipe)
>> bricks/export-raid-vol.log-20150517:[2015-05-14 17:06:52.636949] E
>> [changelog-helpers.c:280:changelog_handle_change] 0-vol-changelog:
>> Problem
>> rolling over changelog(s)
>> 
>> gluster vol status is all fine, and change-log options are enabled in
>> vol
>> file
>> 
>> volume vol-changelog
>> type features/changelog
>> option changelog on
>> option changelog-dir /export/raid/vol/.glusterfs/changelogs
>> option changelog-brick /export/raid/vol
>> subvolumes vol-posix
>> end-volume
>> 
>> Any help will be appreciated :)
>> 
>> Oh Btw, hard to stop / restart the volume as I have around 4k clients
>> connected.
>> 
>> Thanks !
>> 
>> --
>> Cyril Peponnet
>> 
>> 
>> _______________________________________________
>> Gluster-users mailing list
>> Gluster-users at gluster.org
>> http://www.gluster.org/mailman/listinfo/gluster-users
>> 
>>

More information about the Gluster-users mailing list