ATLAS DDM dark data storage dumps

Hi,

For ATLAS DDM, storage dumps (a list of files in each RSE/spacetoken) must be written periodically as described here: Sign in to CERN

My first thought is that something basically like eos find -f $datadir | sed "s|^$datadir||"
e.g. in a cron job should work. However I am curious if anyone has a robust field-tested script, and if it will be efficient for ~ millions of files.
I also wonder if there is a way (e.g. maybe eos cat could be extended?) to pipe the stdout of such a command into stdin of an eos command to write a file, without FUSE. That way the data could be streamed directly into the EOS storage.

If there is a recommended approach based on production experience (e.g. what is used at the ATLAS T0 ?) , I could fill in the empty documentation section for EOS: Sign in to CERN

Thanks!

Hi Ryan, you should use:
eos-ns-inspect
That connects directly to QuarkDB and scans the whole namespace or a subpath without involving the MGM at all.

eos-ns-inspect  -h
Tool to inspect contents of the QuarkDB-based EOS namespace.
Usage: eos-ns-inspect [OPTIONS] SUBCOMMAND

Options:
-h,–help                   Print this help message and exit

Subcommands:
dump                        [DEPRECATED] Recursively dump entire namespace contents under a specific path
scan                        Recursively scan and print entire namespace contents under a specific path
print                       Print everything known about a given file, or container
stripediff                  Find files which have non-nominal number of stripes (replicas)
one-replica-layout          Find all files whose layout asks for a single replica
scan-dirs                   Dump the full list of container metadata across the entire namespace
scan-files                  Dump the full list of file metadata across the entire namespace





1 Like

Thanks Andreas! I worked out this command which seems to work nicely:

eos-ns-inspect scan --relative-paths --raw-paths --no-dirs --path /eos/wlcg-dev.uvic.ca/data/atlas/atlasscratchdisk/ --members eos-qdb.eos.svc:7777   --password-file /etc/eos.keytab  2> /dev/null