Ceph

We already support sending logs to syslog, to stdout, or to a file. We could pretty easily support a fourth option, which is piping them to an arbitrary process. This would be slower than the first three, since it would involve more context switches, but some users might find it useful.

One tricky question is what to do if the filter process dies. I guess either respawn it or give up on it. Or maybe respawn it a few times, then give up if it keeps dying?