llsom_sync(8)

NAME
llsom_sync - Utility to sync file LSOM xattr.

SYNOPSIS
llsom_sync --mdt|-m <mdt> --user|-u <user id>

DESCRIPTION
llsom_sync is designed to sync file LSOM xattr in the Lustre Filesystem by using Lustre MDT changelogs. A changelog user must be registered (see lctl (8) changelog_register) before using this tool.

OPTIONS
--mdt=<mdt>
The metadata device which need to be synced the LSOM xattr of files. A changelog user must be registered for this device. --user=<user id>
The changelog user id for the above MDT device. See lctl(8) changelog_register. --daemonize
Daemonize the program. In daemon mode, the utility will scan, process the changelog records and sync the LSOM xattr for files periodically. --verbose
Produce a verbose output. --interval
The time interval to scan the Lustre changelog and process the log record in daemon mode. --min-age
The time that llsom_sync tool will not try to sync the SOM data for any files closed less than this many seconds old. The default min-age value is 600s (10 minutes). --max-cache
The total memory used for the FID cache which can be with a suffix [KkGgMm]. The default max-cache value is 256MB. For the parameter value < 100, it is taken as the percentage of total memory size used for the FID cache instead of the cache size. --sync
Sync file data to make the dirty data out of cache to ensure the blocks count is correct when update the file LSOM xattr. This option could hurt server performance significantly if thousands of fsync requests are sent.

EXAMPLES

Register a changelog consumer for MDT lustre-MDT0000
    $ cl_user=$(ssh root@mds01 lctl --device lustre-MDT0000 changelog_register -n)
    $ echo $cl_user
    cl1

After perform some file operations on the Lustre Filesystem with
    mount point '/mnt/lustre' and the filesystem undergoes some changes, sync file LSOM xattr: $ llsom_sync --mdt=lustre-MDT0000 --user=$cl_user \
                 --verbose /mnt/lustre

To deregister the changelog user (e.g. after this example, or if SOM
    updates are no longer needed):
    $ ssh root@mds01 lctl --device lustre-MDT0000 changelog_deregister $cl_user

AUTHOR
The llsom_sync command is part of the Lustre filesystem.

SEE ALSO
lustre(7), lctl(8)