Shared disk files synchronization

Question

I have two Centos 7 servers with a shared disk mounted via fstab with:

/dev/sdb /mnt/shared   xfs  rw,suid,dev,noexec,auto,user,sync      0  0

I can see the disk and its content on both servers, but when I create a new file it is not automatically seen on the opposite server. If I umount and mount the disk, then the files will appear.

Executing sync after file creation also won't create the file.

I have installed lsyncd as suggested here but nothing changed.

Are you using clustered XFS? If not you will be at serious risk of corrupting your filesystem, if both are mounted r/w — rusty shackleford, Jun 07 '18 at 13:50
No problem! Posted as an answer with some example clustered filesystems. — rusty shackleford, Jun 07 '18 at 14:20

score 1 · Accepted Answer · answered Jun 07 '18 at 14:19

1

If you are using a shared block device you must ensure you are using a clustered filesystem if you intend for both servers to be able to write to the filesystem. Otherwise you will undoubtedly corrupt the file system.

Examples of clustered file systems:

GFS
Lustre
OCF
LizardFS

If it's an option, it may be simpler to mount an NFS share on both servers, as this will handle file locking etc.

answered Jun 07 '18 at 14:19

rusty shackleford

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btrfs would be a valid one? https://www.mopar4life.com/btrfs-centos-samba/ – Zumo de Vidrio Jun 08 '18 at 07:19
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No `btrfs` is not a clustered filesystem, and it doesn't look like they plan on making it one: https://btrfs.wiki.kernel.org/index.php/FAQ#Will_Btrfs_become_a_clustered_file_system – rusty shackleford Jun 08 '18 at 07:50

Shared disk files synchronization

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