[gpfsug-discuss] fast ACL alter solution

Martin Gasthuber martin.gasthuber at desy.de
Tue Jul 28 17:28:44 BST 2015


Hi,

  since a few months we're running a new infrastructure, with the core built on GPFS (4.1.0.8), for 'light source - X-Rays' experiments local at the site. The system is used for the data acquisition chain, data analysis, data exports and archive. Right now we got new detector types (homebuilt, experimental) generating millions of small files - the last run produced ~9 million files at 64 to 128K in size ;-). In our setup, the files gets copied to a (user accessible) GPFS instance which controls the access by NFSv4 ACLs (only !) and from time to time, we had to modify these ACLs (add/remove user/group etc.). Doing a (non policy-run based) simple approach, changing 9 million files requires ~200 hours to run - which we consider not really a good option. Running mmgetacl/mmputacl whithin a policy-run will clearly speed that up - but the biggest time consuming operations are the get and put ACL ops. Is anybody aware of any faster ACL access operation (whithin the policy-run) - or even a 'mod-acl' operation ?

best regards,
  Martin




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