2016: Greencube migration, Hera end-of-life

• 2016-03: The Nyx servers and the Kronos cluster have been moved to the new GreenITCube

Copying data between clusters

As of 2016-05-18, six machines can be used to copy data from Hera to Nyx:

• lxheranyxdm01
• lxheranyxdm03
• lxheranyxdm05
• lxheranyxdm06
• lxheranyxdm07
• lxheranyxdm08

Peculiarities

Caveat: Hera is mounted as /lustre/hera and Nyx as /lustre/nyx.

The heranyxdm machines are just for copying. Home directories are created on the fly during login.

The heranyxdm machines are running the Hera-version of Lustre. This older version does not know about multiple MDS, a feature we are employing in Nyx.

• Hence, if you do a ls /lustre/nyx on one of the boxes, you will get an error message:

troth@lxheranyxdm03:~$ ls /lustre/nyx
ls: cannot access /lustre/nyx/mdt1: Input/output error
alice  ap  bhs  cbm  fairgsi  fn  fopi  hades  hij  hpc  htit  hyihp  land  lcsc  lobi  mdt1  panda  rz  sids  theory  ukt

• This is harmless: you cannot access this one directory mdt1 from these boxes, but all the rest is there.
  • mdt1 is registered with the second MDS of Nyx, hence this situation.

Space considerations

Given the as-of-yet smaller total amount of space on Nyx, this is the time for cleaning up your directories and getting rid of all the old stuff!

Streamline copy processes

To avoid the time consuming steps involved in recursive copying, as in cp -r or rsync -a, try a variant of

• lfs find MyDir -print0 | parallel -0 -j4 rsync -vlptgoDAXdRqW {} /lustre/nyx/Destination

This obviously works in a /lustre/hera/Subdirectory wherein you have your MyDir.

lfs find should work better than pure find, and you must avoid the recursive flag -r in the collection of rsync-options.