Ceph » CephFS

Hi,

We noticed that df -i on our cehpfs was a bit odd:

Filesystem                                                 Inodes IUsed IFree IUse% Mounted on
10.xx.xx.xx:6789,10.xx.xx.xx:6789,10.xx.xx.xx:6789:/svp/ 10984832     -     -     - /mnt/cephfs

Stracing I find this:

statfs("/mnt/cephfs", {f_type=0xc36400, f_bsize=4194304, f_blocks=15611049, f_bfree=7289822, f_bavail=7289822, f_files=10979519, f_ffree=18446744073709551615, f_fsid={1894312162, 282397230}, f_namelen=255, f_frsize=4194304, f_flags=ST_VALID|ST_NOATIME}) = 0

man page shows

           fsfilcnt_t f_files;   /* Total file nodes in filesystem */
           fsfilcnt_t f_ffree;   /* Free file nodes in filesystem */

From the source code it seems clear that f_files is the total number of file nodes in the file system, used or not so it's a bit startling that the number of free nodes is higher than the number of nodes in total.

The nagios checker shows the filesystem to have -.0 free inodes due to quirks of math.

Client kernel is stock centos 7:

Linux svp-encoder-03.int.vgnett.no 3.10.0-862.3.3.el7.x86_64 #1 SMP Fri Jun 15 04:15:27 UTC 2018 x86_64 x86_64 x86_64 GNU/Linux

On the server side we run "luminous" on stock CentOS 7. The package versions are 12.2.5-0.el7.x86_64