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

Thu May 28 16:42:57 UTC 2015

One more thing:

nfs.volume-access read-only works only for nfs clients, glusterfs client have still write access

features.read-only on need a vol restart and set RO for everyone but in this case, geo-rep goes faulty.

[2015-05-28 09:42:27.917897] E [repce(/export/raid/usr_global):188:__call__] RepceClient: call 8739:139858642609920:1432831347.73 (keep_alive) failed on peer with OSError
[2015-05-28 09:42:27.918102] E [syncdutils(/export/raid/usr_global):240:log_raise_exception] <top>: FAIL:
Traceback (most recent call last):
  File "/usr/libexec/glusterfs/python/syncdaemon/syncdutils.py", line 266, in twrap
    tf(*aa)
  File "/usr/libexec/glusterfs/python/syncdaemon/master.py", line 391, in keep_alive
    cls.slave.server.keep_alive(vi)
  File "/usr/libexec/glusterfs/python/syncdaemon/repce.py", line 204, in __call__
    return self.ins(self.meth, *a)
  File "/usr/libexec/glusterfs/python/syncdaemon/repce.py", line 189, in __call__
    raise res
OSError: [Errno 30] Read-

So there is no proper way to protect the salve against write.

--
Cyril Peponnet

On May 28, 2015, at 8:54 AM, Cyril Peponnet <cyril.peponnet at alcatel-lucent.com<mailto:cyril.peponnet at alcatel-lucent.com>> wrote:

Hi Kotresh,

Inline.

Again, thank for you time.

--
Cyril Peponnet

On May 27, 2015, at 10:47 PM, Kotresh Hiremath Ravishankar <khiremat at redhat.com<mailto:khiremat at redhat.com>> wrote:

Hi Cyril,

Replies 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: Wednesday, May 27, 2015 9:28:00 PM
Subject: Re: [Gluster-users] Geo-Replication - Changelog socket is not present - Falling back to xsync

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.

Resetting index does not initiate geo-replication from the version changelog is
introduced. It works only for the versions prior to it.

NOTE 1: Recreation of geo-rep session will work only if slave doesn't contain
      file with mismatch gfids. If there are, slave should be cleaned up
      before recreating.

I started it again to transfert missing files Ill take of gfid missmatch afterward. Our vol is almost 5TB and it took almost 2 month to crawl to the slave I did’nt want to start over :/

NOTE 2: Another method exists now to initiate a full sync. It also expects slave
        files should not be in gfid mismatch state (meaning, slave volume should not
        written by any other means other than geo-replication). The method is to
        reset stime on all the bricks of master.

        Following are the steps to trigger full sync!!!. Let me know if any comments/doubts.
        ================================================
        1. Stop geo-replication
        2. Remove stime extended attribute all the master brick root using following command.
           setfattr -x trusted.glusterfs.<MASTER_VOL_UUID>.<SLAVE_VOL_UUID>.stime <brick-root>
          NOTE: 1. If AFR is setup, do this for all replicated set

                2. Above mentioned stime key can be got as follows:
                   Using 'gluster volume info <mastervol>', get all brick paths and dump all the
                   extended attributes, using 'getfattr -d -m . -e hex <brick-path>', which will
                   dump stime key which should be removed.

                3. The technique, re-triggers complete sync. It involves complete xsync crawl.
                   If there are rename issues, it might hit the rsync error on complete re-sync as well.
                   So it is recommended, if the problematic files on slaves are known, remove them and initiate
                   complete sync.

Is complete sync will send again the data if present of not ? How to track down rename issue ? master is a living volume with lot of creation / rename / deletion.

        3. Start geo-replicatoin.

        The above technique can also be used to trigger data sync only on one particular brick.
        Just removing stime extended attribute only on brick root of master to be synced will
        do. If AFR is setup, remove stime on all replicated set of bricks.

        ================================

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.

    In newer geo-replication, from the version history crawl is introduced, xsync
crawl is minimized. Once it reaches the timestamp where it gets the historical changelogs,
it starts using history changelogs. Touch will be recorded as SETATTR in Changelog so
Geo-rep will not sync the data. So the new virtual setattr interface is introduced
which is mentioned in previous mail.

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 ?

No, it is not recursive, it should be done for every missing files and directories.
And directories should be done before the files inside it.
It should be done on master.

I don’t understand the difference between setfattr -n glusterfs.geo-rep.trigger-sync -v “1” <DIR> (vol level) and setfattr -x trusted.glusterfs.<MASTER_VOL_UUID>.<SLAVE_VOL_UUID>.stime <brick-root> (brick level)

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 ?

Yes, that should do.

Cool ! Thanks!

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

On May 26, 2015, at 11:29 PM, Kotresh Hiremath Ravishankar
<khiremat at redhat.com<mailto: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<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: 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><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><mailto:cyril.peponnet at alcatel-lucent.com>>
To: "Kotresh Hiremath Ravishankar"
<khiremat at redhat.com<mailto:khiremat at redhat.com><mailto:khiremat at redhat.com>>
Cc: "gluster-users"
<gluster-users at gluster.org<mailto: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><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><mailto:cyril.peponnet at alcatel-lucent.com>>
To: "Kotresh Hiremath Ravishankar"
<khiremat at redhat.com<mailto:khiremat at redhat.com><mailto:khiremat at redhat.com>>
Cc: "gluster-users"
<gluster-users at gluster.org<mailto: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><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><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><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><mailto:cyril.peponnet at alcatel-lucent.com>>
To: "gluster-users"
<gluster-users at gluster.org<mailto: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

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