wiki:developers-meeting-20071017
Last modified 5 years ago

dCache developers phone conference Oct 17

Participated : Timur, Ted, Tanja, Alex, Vladimir, Gene, Tigran and Patrick

  • The Nebraska issue : With the most recent dCache 1.7 the orphan file issue seemed be solved.
  • Preparation of dCache SRM 2.2 documenation : Initial version should be done till mid of next week. Timur will send the document to srm-deployment for comments.
  • Timur will add a command to enable/disable the SpaceManager to allow a smooth migration 1.7 -> 1.8 w/o SM -> 1.8 w SM without having the batch files of the doors modified by the sysadmins.
  • 1.7 issues at FERMI (USCMS) : After tuning the SRM (gPlazma) for Jon installation, it seems pnfs is becoming the next bottleneck. Facts :
    • There are about 40 threads in the pnfsManager from which each has a queue lenght of 10 - 50.
    • The total rate of (read/write) of dCache files is in the order of 6/sec.
    • The number of nfs ops is in the order of 3000/sec. Compare with DESY this is much to high.
    • Actions :
      • Find an Linux expert who can tell us which part of the Pnfs LInux system is the limiting factor.
      • Talk to the CMS Framework manager to findout which additional nfs meta data operations are performed.
      • Findout what the pools are actually doing with pnfs.

Last modified by patrick @ Wed May 23 10:11:02 2012