The sync command introduced in
CVM-1552 is causing problems on the FNAL stratum 1 pair of servers. Filesystem accesses are running extremely slow, and I see 100% cpu on a sync process running much of the time while snapshot waits. It is running cvmfs-2.5.1. I think the filesystem itself may also be slow, but this appears to be making it worse. I don't see a corresponding problem on the new zfs-based UNL stratum 1 which is also running cvmfs-2.5.1. On the other hand on the old zfs-based UNL ITB stratum 1 I am also seeing a lot of sync activity in "top". I'm going to recommend to the FNAL stratum 1 administrator to comment out the sync command in /usr/bin/cvmfs_server to see how that affects things.
At a minimum this should probably be a configurable option.