The tool gfind_missing_files.sh can be used to find the missing files in a GlusterFS geo-replicated slave volume. The tool uses a multi-threaded crawler operating on the backend .glusterfs of a brickpath which is passed as one of the parameters to the tool. It does a stat on each entry in the slave volume mount to check for the presence of a file. The tool uses the aux-gfid-mount thereby avoiding path conversions and potentially saving time.
This tool should be run on every node and each brickpath in a geo-replicated master volume to find the missing files on the slave volume.
The script gfind_missing_files.sh is a wrapper script that in turn uses the gcrawler binary to do the backend crawling. The script detects the gfids of the missing files and runs the gfid-to-path conversion script to list out the missing files with their full pathnames.
$bash gfind_missing_files.sh <BRICK_PATH> <SLAVE_HOST> <SLAVE_VOL> <OUTFILE> BRICK_PATH - Full path of the brick SLAVE_HOST - Hostname of gluster volume SLAVE_VOL - Gluster volume name OUTFILE - Output file which contains gfids of the missing files
The gfid-to-path conversion uses a quicker algorithm for converting gfids to paths and it is possible that in some cases all missing gfids may not be converted to their respective paths.
Example output(126733 missing files)
$ionice -c 2 -n 7 ./gfind_missing_files.sh /bricks/m3 acdc slave-vol ~/test_results/m3-4.txt Calling crawler... Crawl Complete. gfids of skipped files are available in the file /root/test_results/m3-4.txt Starting gfid to path conversion Path names of skipped files are available in the file /root/test_results/m3-4.txt_pathnames WARNING: Unable to convert some GFIDs to Paths, GFIDs logged to /root/test_results/m3-4.txt_gfids Use bash gfid_to_path.sh <brick-path> /root/test_results/m3-4.txt_gfids to convert those GFIDs to Path Total Missing File Count : 126733
In such cases, an additional step is needed to convert those gfids to paths. This can be used as shown below:
$bash gfid_to_path.sh <BRICK_PATH> <GFID_FILE> BRICK_PATH - Full path of the brick. GFID_FILE - OUTFILE_gfids got from gfind_missing_files.sh
Things to keep in mind when running the tool
- Running this tool can result in a crawl of the backend filesystem at each brick which can be intensive. To ensure there is no impact on ongoing I/O on RHS volumes, we recommend that this tool be run at a low I/O scheduling class (best-effort) and priority.
$ionice -c 2 -p <pid of gfind_missing_files.sh>
- We do not recommend interrupting the tool when it is running (e.g. by doing CTRL^C). It is better to wait for the tool to finish execution. In case it is interrupted, manually unmount the Slave Volume.