Current GlusterFS Geo-replication is GFID based, that means the file in Secondary site will have same GFID of the file exists in Primary Volume. This approach introduces the following issues.
-
Two Step operations Entry operations and data sync operations are different, Entry operations are done using
RPCand then data synced usingrsync. -
Rsync --inplace option Normally rsync creates a temporary file and then it renames to final file name to prevent corruption and also for data availability for reading. But creating new file means changing the GFID. So existing Geo-replication uses
--inplaceoption to prevent the same. -
Multiple Revisions If a file is created, deleted and then created again(Example: Log rotate), then same steps should be replayed on Secondary state to get the same GFID.
-
No support for non GlusterFS targets Because of the GFID dependency, Geo-replication can’t be setup for non GlusterFS volume targets.
Create the config file as
# filename: config.yaml
source_dir: /mnt/gvol1
target: server1.kadalu:/mnt/gvol2
crawl_dir: /bricks/gvol1/brick1/brick
stime_xattr: 53d458aa-075c-4a3c-8d69-62ac4802d41b.stimeWhere
-
source_diris path of Primary Volume mount -
targetis the hostname and target directory details.<secondary-node>:<secondary-volume-mount>format -
crawl_diris the Brick root from where Crawl is done. -
stime_xattris the name of the xattr to be maintained to record the synced time. Ideally<secondary-vol-id>.stime
Now run the Geosync,
# mkdir -p /root/.ssh/controlmasters
# ssh-keygen
# # ssh-copy-id <secondary-hostname>, for example
# ssh-copy-id [email protected]
# ./geosync config.yaml