[Gluster-users] volume process does not start - glusterfs is happy with it?

[lejeczek]

On 30/06/2020 11:31, Barak Sason Rofman wrote:
> Greetings,
>
> I'm not sure if that's directly related to your problem,
> but on a general level, AFAIK, replica-2 vols are not
> recommended due to split brain possibility:
> https://docs.gluster.org/en/latest/Administrator%20Guide/Split%20brain%20and%20ways%20to%20deal%20with%20it/
>
> It's recommended to either use replica-3 or arbiter Arbiter.
>
> Regards,
>
> On Tue, Jun 30, 2020 at 1:14 PM lejeczek
> <peljasz at yahoo.co.uk <mailto:peljasz at yahoo.co.uk>> wrote:
>
>     Hi everybody.
>
>     I have two peers in the cluster and a 2-replica volume
>     which seems okey if it was not for one weird bit -
>     when a peer reboots then on that peer after a reboot I
>     see:
>
>     $ gluster volume status USERs
>     Status of volume: USERs
>     Gluster process                             TCP Port 
>     RDMA Port  Online  Pid
>     ------------------------------------------------------------------------------
>     Brick swir.direct:/00.STORAGE/2/0-GLUSTER-U
>     SERs                                        N/A      
>     N/A        N       N/A 
>     Brick dzien.direct:/00.STORAGE/2/0-GLUSTER-
>     USERs                                       49152    
>     0          Y       57338
>     Self-heal Daemon on localhost               N/A      
>     N/A        Y       4302
>     Self-heal Daemon on dzien.direct            N/A      
>     N/A        Y       57359
>      
>     Task Status of Volume USERs
>     ------------------------------------------------------------------------------
>     There are no active volume tasks
>
>     I do not suppose it's expected.
>     On such rebooted node I see:
>     $ systemctl status -l glusterd
>     ● glusterd.service - GlusterFS, a clustered
>     file-system server
>        Loaded: loaded
>     (/usr/lib/systemd/system/glusterd.service; enabled;
>     vendor preset: enabled)
>       Drop-In: /etc/systemd/system/glusterd.service.d
>                └─override.conf
>        Active: active (running) since Mon 2020-06-29
>     21:37:36 BST; 13h ago
>          Docs: man:glusterd(8)
>       Process: 4071 ExecStart=/usr/sbin/glusterd -p
>     /var/run/glusterd.pid --log-level $LOG_LEVEL
>     $GLUSTERD_OPTIONS (code=exited, status>
>      Main PID: 4086 (glusterd)
>         Tasks: 20 (limit: 101792)
>        Memory: 28.9M
>        CGroup: /system.slice/glusterd.service
>                ├─4086 /usr/sbin/glusterd -p
>     /var/run/glusterd.pid --log-level INFO
>                └─4302 /usr/sbin/glusterfs -s localhost
>     --volfile-id shd/USERs -p
>     /var/run/gluster/shd/USERs/USERs-shd.pid -l /var/log/g>
>
>     Jun 29 21:37:36 swir.private.pawel systemd[1]:
>     Starting GlusterFS, a clustered file-system server...
>     Jun 29 21:37:36 swir.private.pawel systemd[1]: Started
>     GlusterFS, a clustered file-system server.
>
>     And I do not see any other apparent problems nor errors.
>     On that node I manually:
>     $ systemctl restart glusterd.service
>     and...
>
>     $ gluster volume status USERs
>     Status of volume: USERs
>     Gluster process                             TCP Port 
>     RDMA Port  Online  Pid
>     ------------------------------------------------------------------------------
>     Brick swir.direct:/00.STORAGE/2/0-GLUSTER-U
>     SERs                                        49152    
>     0          Y       103225
>     Brick dzien.direct:/00.STORAGE/2/0-GLUSTER-
>     USERs                                       49152    
>     0          Y       57338
>     Self-heal Daemon on localhost               N/A      
>     N/A        Y       103270
>     Self-heal Daemon on dzien.direct            N/A      
>     N/A        Y       57359
>
>     Is not a puzzle??? I'm on glusterfs-7.6-1.el8.x86_64
>     I hope somebody can share some thoughts.
>     many thanks, L.
>
That cannot be it!? If the root cause of this problem is
2-replica volume then it would be a massive cock-up! Then
2-volume replica should be banned and forbidden.

I hope some can suggest a way to troubleshoot it.

ps. we all, I presume all, know problems of 2-replica volumes.

many thanks, L.


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> -- 
> *Barak Sason Rofman*
>
> Gluster Storage Development
>
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