We are using rsnapshot for backups. It uses hard links to efficiently store unchanged files, and rsyncs the changed files from servers.

The hard linking part calls a command like this

  cp -al /current /old

But this process uses up ALL the available memory. Is there a way to limit memory of cp process, or is there a memnice utility a la nice/ionice?

1 Answer 1


rsnapshot includes support for --link-dest support using rsync which would avoid the cp -al step. Rsync 3.0+ doesn't have to keep the entire directory tree in memory and would probably work better in your situation.

  • 1
    The --link-dest patch was written by the original author of dirvish (which is similar to rsnapshot but more complex/powerful), probably to overcome the limitations of cp -al.
    – Andrew
    Jul 1, 2010 at 3:31
  • that changed the backup time from 15+ hours to just 6 hours. Thanks :)
    – hayalci
    Jul 5, 2010 at 8:11
  • There's more discussion on an alternative technique here - basically rotating the last hourly snapshot into the new one and doing a cp -afl from hourly.1 onto hourly.0 but I haven't tried that - you'd have to do the rotation manually rather than relying on rsnapshot to do it Jul 22, 2011 at 8:00
  • @DavidFraser The link is broken.
    – Koshur
    Jun 25, 2019 at 5:24
  • Found an updated link: rsnapshot-discuss Speeding up rsnapshot: eliminating the cp -al Jun 26, 2019 at 10:27

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