When downloading files from external data servers and the cache is almost file, the cvmfs client does frequent cache cleanups, with messages in /var/log/messages like this:
This is because the default chunk size for cvmfs_server graft is 32MB and, as discussed in
CVM-1128, the cvmfs ciient will do an immediate garbage collection for the requested chunk size when it is larger than kBigFile parameter which is 25MB.
In the previous ticket, Brian said we would fix it by reducing the setting done at run-time, but he has since said he thinks there should not be a mismatch in the defaults. I plan to increase kBigFile to 33MB.