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RRZ
Regional Computer
Center (RRZ)

Photo: Thomas Orgis

Hummel → Hummel-2 Migration Guide

This guide describes steps for migrating from Hummel to Hummel-2.

Big changes

We tried to keep changes of Hummel concepts minimal. Big changes on Hummel-2 compared with Hummel are:

  • Batch jobs
    • All compute nodes are fat. As a consequence batch jobs most will share a node with other jobs.
    • sbatch option --mail-user is ignored. If --mail-type is set e-mail(s) will be sent to the e-mail on the Hummel-2 mailing list.
  • Disks
    • The compute notes have no local/scratch disks. /tmp, /dev/shm and $RRZ_LOCAL_TMPDIR are RAM disks.
    • There is an SSD pool in addition to the BeeGFS parallel file system that is based on spinning disks. A consequence of the SSD pool approach is that adequate usage of disk systems can only be planned on an individual basis. Please contact the HPC team if you have questions concerning disk usage. At the beginning every user has 100 GB disk space in $SSD.
    • $BEEGFS replaces $WORK. Technically both underlying filesystems are very similar, but on Hummel-2 an SSD filesystem can become the working file system (and $BEEGFS the backup file filesystem).

Usernames and Unix groups

On Hummel-2:

  • All usernames have the B-Kennung format: bxy1234.
  • For each username exists a Unix group with the same name, which is the primary Unix group.
  • Every user is also member of a Unix group that represents the working group.
    • That group can be used for sharing files.
    • The id command prints Unix group memberships.

Software

Software installed by RRZ

  • With the software installed it should be possible to compile all kinds of code.
  • Recall that switching to a pkgsrc Module
          module switch env env/2023Q4-gcc-openmpi
    provides many tools and the R software.
  • Application software packages will be installed soon.

Software installed by yourself

  • All software needs to be reinstalled.
  • Please install large software packages downloaded from the internet in $USW (rather than in $HOME). See also Which file system to use when?.

Data

Please read also: Working with data.

Which data to migrate?

  • Be careful when copying data to $HOME! In particular, make sure that you do not overwerite any files in the $HOME/.ssh/ directory.
  • Probably not much needs to be copied from $USW, see Software above.
  • Take the opportunity to cleanup $WORK, i.e. copy only data that is still needed.

How to migrate/copy data from Hummel

  • On the Hummel-2 login gateways
          hummel3.rrz.uni-hamburg.de
          hummel4.rrz.uni-hamburg.de
    files from Hummel can be copied with scp, sftp or rsync via the Hummel login gateways
          hummel1.rrz.uni-hamburg.de
          hummel2.rrz.uni-hamburg.de
  • Example (on Hummel-2: copy all files in a directory from Hummel $WORK to $BEEGFS)
          bxy1234@hummel2-login1:~$ cd $BEEGFS
          bxy1234@hummel2-login1:/beegfs/u/bxy1234$ scp -pr \
                hummel1.rrz.uni-hamburg.de:/work/bxy1234/directory1 .
  • Note that your Hummel-1 username is unchanged, i.e. it might differ from your Hummel-2 username.