Ceph: Designing and Implementing Scalable Storage Systems

Logs

Ceph performs extensive logging. Ceph can be configured to log directly through the central syslog or rsyslog service, but by default, it writes to local files. These are managed by the stock Linux logrotate facility. Here's the default rotation stanza that the Ceph Jewel release installs.

# cat /etc/logrotate.d/ceph.logrotate
/var/log/ceph/*.log {
    rotate 7
    daily
    compress
    sharedscripts
    postrotate
        killall -q -1 ceph-mon ceph-mds ceph-osd ceph-fuse radosgw               || true
    endscript
    missingok
    notifempty
    su root ceph
}

The default retention is 7 days, which this author at times finds to be too short. To increase to four weeks, replace the 7 with 30, but be careful that the filesystem where /var/log lives has adequate free space. As we ...