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Compression Level for -z9p

nicdai
4 days ago
24 hours ago
  • nicdai

    nicdai - 4 days ago

    How can I change the compression level when using -z9p (zstd -T0)?

    The used/default level is 3. I have already tried changing drbl-ocs.conf by replacing all occurences of -3 to another level. But any changes are ignored by Clonezilla. The used compression level is always 3.

     
  • Steven Shiau

    Steven Shiau - 2 days ago

    The priority is:

    1. /etc/ocs/ocs-live.conf (only exists for Clonezilla live, not Clonezilla SE)
    2. /etc/drbl/drbl-ocs.conf

    For live system, you can also assign the following in the boot parameter:
    extra_zstd_opt="-T0 -3"
    Change "-3" to what you want. However, normally it's not worthy since the time spent is much longer but the size does not reduce too much.

     
  • nicdai

    nicdai - 1 day ago

    Thanks for sharing this information. I hopefully now understand the configuration process.

    For my setup, using "-6" instead of "-3" gives more performance (+5%) and better compression.

    Compression levels greater than 6 result in less performance. But at 6 the CPU is yet not fully utilized. So I think that there is some bottleneck with partclone and perhaps the checksum calculations or the network.

    Anyway, its an interesting journey. I'm now at ~70GB/min, and I think that there is still room for improvements.

    With a lot of configuration and tweaks I was able to get this performance from initially ~30GB/min for Core 9 Ultra and the 10G network. Especially tuning NIC parameters helped a lot.

     
  • Steven Shiau

    Steven Shiau - 24 hours ago

    Great. Thanks for sharing that. The "~70GB/min" is quite amazing. Nice to know that.
    Absolutely there is still room for improvements.
    Let us know if you find the common factors that can improve the performance in general.

     

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