[Gluster-users] geo-replication initial setup with existing data

[Kotresh Hiremath Ravishankar]

Hi,

Geo-replication expects the gfids (unique identifier similar to inode
number in backend file systems) to be same
for a file both on master and slave gluster volume. If the data is directly
copied by other means other than geo-replication,
gfid will be different. The crashes you are seeing is because of that.

If the data is not huge, I would recommend to sync the data from master
volume using geo-replication. The other way
is to copy directly to slave and set the gfid at the backend for each file
to be same as in master volume and then setup
geo-replication. To do the latter, follow below steps. (Note that it's not
tested extensively)


   1. Run the following commands on any one of the master nodes:

   # cd /usr/share/glusterfs/scripts/
   # sh generate-gfid-file.sh localhost:${master-vol} $PWD/get-gfid.sh
/tmp/tmp.*atyEmKyCjo*/upgrade-gfid-values.txt
   # scp /tmp/tmp.*atyEmKyCjo*/upgrade-gfid-values.txt root@${slavehost}:/tmp/

   2. Run the following commands on a slave node:

   # cd /usr/share/glusterfs/scripts/
   # sh slave-upgrade.sh localhost:${slave-vol}
/tmp/tmp.*atyEmKyCjo*/upgrade-gfid-values.txt $PWD/gsync-sync-gfid

   3. Setup geo-rep and start


Thanks,
Kotresh HR

On Mon, Jan 22, 2018 at 4:55 PM, <tino_maier at gmx.de> wrote:

> Hello everyone,
>
> i was searching for a replacement of my rsync dublication of data to
> second server and ended up with gluster geo-replicaiton. But after reading
> the documentation and lots of websites I'm still unsure how to setup a
> geo-replication without retransfering all data.
> I succeeded in converting my existing data folder to a gluster volume by
> creating a volume and using the "find /media/brick -noleaf -print0 | xargs
> --null stat" inside the mounted gluster volume folder on the master.
> But how to I have to prepare the slave? I try to do it in the same way as
> with the master, but this will only result in error messages like
> [2018-01-22 11:17:05.209027] E [repce(/media/brick):209:__call__]
> RepceClient: call failed on peer call=27401:140641732232960:1516619825.12
>        method=entry_ops        error=OSError
> [2018-01-22 11:17:05.209497] E [syncdutils(/media/brick):331:log_raise_exception]
> <top>: FAIL:
> Traceback (most recent call last):
>   File "/usr/lib/x86_64-linux-gnu/glusterfs/python/syncdaemon/gsyncd.py",
> line 210, in main
>     main_i()
>   File "/usr/lib/x86_64-linux-gnu/glusterfs/python/syncdaemon/gsyncd.py",
> line 801, in main_i
>     local.service_loop(*[r for r in [remote] if r])
>   File "/usr/lib/x86_64-linux-gnu/glusterfs/python/syncdaemon/resource.py",
> line 1670, in service_loop
>     g1.crawlwrap(oneshot=True, register_time=register_time)
>   File "/usr/lib/x86_64-linux-gnu/glusterfs/python/syncdaemon/master.py",
> line 597, in crawlwrap
>     self.crawl()
>   File "/usr/lib/x86_64-linux-gnu/glusterfs/python/syncdaemon/master.py",
> line 1555, in crawl
>     self.process([item[1]], 0)
>   File "/usr/lib/x86_64-linux-gnu/glusterfs/python/syncdaemon/master.py",
> line 1204, in process
>     self.process_change(change, done, retry)
>   File "/usr/lib/x86_64-linux-gnu/glusterfs/python/syncdaemon/master.py",
> line 1114, in process_change
>     failures = self.slave.server.entry_ops(entries)
>   File "/usr/lib/x86_64-linux-gnu/glusterfs/python/syncdaemon/repce.py",
> line 228, in __call__
>     return self.ins(self.meth, *a)
>   File "/usr/lib/x86_64-linux-gnu/glusterfs/python/syncdaemon/repce.py",
> line 210, in __call__
>     raise res
> OSError: [Errno 42] .gfid/00000000-0000-0000-0000-000000000001
> I removed now all extended attributes on the slave and deleted the
> .glusterfs folder in the brick, so the system is hopefully in the inital
> state again.
> Is there any way to setup a geo-replication session without resyncing all
> data by gluster? Because this will take month with my poor connection over
> here. I'm using gluster 3.13.1 on two Ubuntu 16.04.3 LTS hosts.
>
> I hope someone can help me with some hints, thanks and best regards
> Tino
>
>
>
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>



-- 
Thanks and Regards,
Kotresh H R
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