[LU-11024] Broken inode accounting of MDT on ZFS

Related — Mon, 28 May 2018 02:11:00 +0000

Roughly 6,200 10MB files are created with 'dd' loop:

[thcrowe@td-mngt01 thcrowe] for i in `seq 1 10000` ; do dd if=/dev/zero of=file-$i bs=1M count=10; done
^C
[thcrowe@td-mngt01 thcrowe]

All files were written to MDT index 0.

[thcrowe@td-mngt01 thcrowe]$ lfs getstripe ~~m file~~* | sort | uniq
0
[thcrowe@td-mngt01 thcrowe]$ ls ~~1 file~~* | wc -l
6208

So at this point, POSIX says I have 6,208 files named file-*.
Lustre however, reports the numbers differently.

[thcrowe@td-mngt01 thcrowe]$ lfs quota -u 415432 /mnt/slate
Disk quotas for usr 415432 (uid 415432):
Filesystem kbytes quota limit grace files quota limit grace
/mnt/slate 61619203 0 0 - 1473 0 0 -
[thcrowe@td-mngt01 thcrowe]$

Here is the same data directly from the MDT

[root@slate-mds01 ~]# grep -A1 415432 /proc/fs/lustre/osd-zfs/slate-MDT0000/quota_slave/acct_user

id: 415432
usage: { inodes: 1473, kbytes: 53825 }
[root@slate-mds01 ~]#

Following commands were used to dump MDT index 0's zfs contents:

[root@slate-mds01 ~]# zpool list
NAME SIZE ALLOC FREE EXPANDSZ FRAG CAP DEDUP HEALTH ALTROOT
mgs 186G 6.35M 186G - 0% 0% 1.00x ONLINE -
slate_mdt0000 8.67T 16.1G 8.66T - 0% 0% 1.00x ONLINE -
[root@slate-mds01 ~]# zpool set cachefile=/tmp/slate_mdt0000.cache slate_mdt0000
[root@slate-mds01 ~]# cp /tmp/slate_mdt0000.cache /tmp/slate_mdt0000.cache1
[root@slate-mds01 ~]# zpool set cachefile="" slate_mdt0000
[root@slate-mds01 ~]# zdb -ddddd -U /tmp/slate_mdt0000.cache1 slate_mdt0000 > /tmp/slate_mdt0000-zdb-ddddd

Once the zdb completed it output, it is a simple grep to see what uid 415432 has going on.

[root@slate-mds01 ~]# grep uid /tmp/slate_mdt0000-zdb-ddddd | grep -c 415432
6210

6210 is not 6208, because there are 2 directory objects owned by 415432 in the zdb output.

Further tests were run to check /proc/fs/lustre/osd-zfs/slate-MDT0000/quota_slave/acct_user reported correct information. If created 100 files, the account number increased from 120 to 205, and if created 1000 files, the account number increased from 120 to 929.

Space accounting on MDT works well.

Whamcloud Community JIRA

[LU-11024] Broken inode accounting of MDT on ZFS