On 11.09.2019 18:19, Robert Trevellyan wrote:
I'm letting ZFS do the compression (using the default of LZ4) with BackupPC handling deduplication. I think you'll find a reasonable consensus that ZFS compression is always a win for storage space (it will store un-compressible data unmodified), whereas ZFS deduplication is best avoided in most cases, mostly due to its high memory usage. It's possible that BackupPC compression would be tighter than LZ4,
Actually, on ZFS you are not limited to LZ4, but in ZFS each file block is compressed independently, that is why in most cases BackupPC compression is higher, though it depends on data. We moved from 77.96G cpool to pool on compressed filesystem recently. Now it consumes 81.2G, so there is not much difference. # zfs get compression,compressratio,recordsize,referenced zroot/bpc/pool NAME PROPERTY VALUE SOURCE zroot/bpc/pool compression gzip-3 local zroot/bpc/pool compressratio 3.87x - zroot/bpc/pool recordsize 128K default zroot/bpc/pool referenced 81,2G - _______________________________________________ BackupPC-users mailing list BackupPC-users@lists.sourceforge.net List: https://lists.sourceforge.net/lists/listinfo/backuppc-users Wiki: http://backuppc.wiki.sourceforge.net Project: http://backuppc.sourceforge.net/
