I have a strange problem that began manifesting after I rebuilt my cluster
a month or so back. A tiny subset of my files on CephFS are being
zero-padded out to the length of ceph.dir.layout.stripe_unit when the files
are later *read* (not when they are written). Tonight I realized the
padding matched the stripe_unit value of 1048576, and changed it to
4194304, which resulted in those files that get padded taking on the new
stripe_unit value. I've since changed it back. I've tried searching Google
for answers, and Ceph bugs, but have had no luck so far.
Current ceph.dir.layout setting for the entire cluster.
$ getfattr -n ceph.dir.layout /ceph/ka
getfattr: Removing leading '/' from absolute path names
# file: ceph/ka
ceph.dir.layout="stripe_unit=1048576 stripe_count=2 object_size=8388608
pool=cephfs_data"
Ceph is mounted on all machines using the kernel driver. The problem is not
isolated to a single machine.
$ grep /ceph/ka /etc/mtab
backupz/ceph/ka /backupz/ceph/ka zfs rw,noatime,xattr,noacl 0 0
172.16.0.11:6789,172.16.0.19:6789:/ /ceph/ka ceph
rw,noatime,nodiratime,name=admin,secret=<hidden>,acl 0 0
Files from a Subversion repository, where the last one was padded after I
tried to check out the repo.
kward@ka02 2016-10-20T22:57:13
%0]/ceph/ka/data/repoz/forestent/forestent/db/revs/0
$ ls -lrt |tail -5
-rw-r--r-- 1 www-data www-data 1079 Oct 20 08:53 877
-rw-r--r-- 1 www-data www-data 1415 Oct 20 08:55 878
-rw-r--r-- 1 www-data www-data 1059 Oct 20 09:01 879
-rw-r--r-- 1 www-data www-data 1318 Oct 20 09:36 880
-rw-r--r-- 1 www-data www-data 4194304 Oct 20 19:18 881
Files stored, then later accessed via WebDAV. Only those files accessed
were subsequently padded.
[kward@ka02 2016-10-20T23:01:42 %0]~/www/webdav/OmniFocus.ofocus
$ ls -l
total 16389
-rw-r--r-- 1 www-data www-data 4194304 Oct 20 20:08
00000000000000=ay-_KSusSw8+jOtYClSC2kx.zip
-rw-r--r-- 1 www-data www-data 1383 Oct 20 19:22
20161020172209=pP4DpDOXAaA.client
-rw-r--r-- 1 www-data www-data 4194304 Oct 20 20:20
20161020182047=pP4DpDOXAaA.client
-rw-r--r-- 1 www-data www-data 4194304 Oct 20 21:11
20161020191117=pP4DpDOXAaA.client
-rw-r--r-- 1 www-data www-data 1309 Oct 20 21:56
20161020195647=jY9iwiPfUhB.client
-rw-r--r-- 1 www-data www-data 4194304 Oct 20 22:04
20161020200427=pP4DpDOXAaA.client
-rw-r--r-- 1 www-data www-data 1309 Oct 20 22:54
20161020205415=jY9iwiPfUhB.client
Cluster lists as healthy. (Yes, I'm aware one of the OSDs is currently
down. The issue was there two months before it went down.)
$ ceph status
cluster f13b6373-0cdc-4372-85a2-66bf2841e313
health HEALTH_OK
monmap e3: 3 mons at {ka01=
172.16.0.11:6789/0,ka03=172.16.0.15:6789/0,ka04=172.16.0.17:6789/0}
election epoch 36, quorum 0,1,2 ka01,ka03,ka04
fsmap e1140219: 1/1/1 up {0=ka01=up:active}, 2 up:standby
osdmap e1234338: 16 osds: 15 up, 15 in
flags sortbitwise
pgmap v2296058: 1216 pgs, 3 pools, 7343 GB data, 1718 kobjects
14801 GB used, 19360 GB / 34161 GB avail
1216 active+clean
Details:
- Ceph 10.2.2 (Ubuntu 16.04.1 packages)
- 4x servers, each with 4x OSDs on HDDs (mixture of 2T and 3T drives);
journals on SSD
- 3x Mons, and 3x MDSs
- Data is replicated 2x
- The only usage of the cluster is via CephFS
Kate
https://ch.linkedin.com/in/kate-ward-1119b9
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