CERN Accelerating science

.sys.a#.* named files and their meaning

Hello all,

We have a directory structure with atomic set on as an attribute, because that atomic nature is desired from a software perspective. I’ve noticed that on occasion I have files that persist on the filesystem named like:

/eos/mycluster/directory/.sys.a#.FILENAME.b1ce154e-d3d5-11e9-bf0c-1a6b8faabea0

The last part, I’m guessing is a time based UUID, and the first part is quite obvious. Why do these persist on occasion? Specifically after some kind of disconnect, or client failure or similar.

They remain, if your the client aborted an upload. There is now a new functionality in the MGM to remove these automatically after 48h. To use that, you have to enable the space tracker:

eos space config space.tracker=on

It has some impact on the creation/s rate. You can see with “eos space tracker” files which are currently ‘in-flight’ and have not committed replicas.

Thank you @apeters. I’ve turned that on our test cluster, and will replicate the scenario that caused this.