[Bacula-users] ZFS and dedup

Since a week, I'm testing backup on a powerful server (32G RAM / 4 CPU).

I do a full backup on weekends and incremental every day of the week.
Why my dedup rate is so low?

[root@Bacula fs01]# zdb -DD bacula

DDT-sha256-zap-unique: 17612028 entries, size 295 on disk, 154 in core

DDT histogram (aggregated over all DDTs):

bucket allocated referenced

______ ______________________________ ______________________________

refcnt blocks LSIZE PSIZE DSIZE blocks LSIZE PSIZE DSIZE

------ ------ ----- ----- ----- ------ ----- ----- -----

1 16.8M 2.10T 1.95T 1.95T 16.8M 2.10T 1.95T 1.95T

Total 16.8M 2.10T 1.95T 1.95T 16.8M 2.10T 1.95T 1.95T

dedup = 1.00, compress = 1.07, copies = 1.00, dedup * compress / copies = 1.07

[root@Bacula fs01]# zpool iostat

capacity operations bandwidth

pool alloc free read write read write

---------- ----- ----- ----- ----- ----- -----

bacula 1,96T 1021G 133 55 3,54M 4,27M

Best regards

Antoine

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