# Dar used within the Max Planck Institute

Who
  Max Planck Institute for Gravitational Physics
Context
  The Atlas computing cluster (HPC)
Start date
  Year 2021
Backup/archive size
  from a few 100GB up to 45TByte (compressed) so far - all in 1 TByte chunks with isolated catalogue
Media used
  locally HDD (NAS/ZFS), remotely tape LTO8/9 I think at the moment
Why dar
  before using regular old tar/star but seqential only access is prohibitively expensive when only need some files from very few chunks in the middle
other remarks
  only downside right now is that it seems to be very slow when generating archive/compressing very large directory structures with a LOT of files. But so far, no real time to investigate on my part, just running something like: `dar --create PROJECT --verbose=messages \ --fs-root /srv/00transfer/PROJECT --alter=binary\ --slice=1T --min-digits=4 \ --compression=zstd:20:1M --multi-thread=12 \ --slice-mode=0600 --hash=sha512`
Source
  Carsten Aulbert in December 2025

Back to page of references