btrfs compression wins

Some quite good btrfs compression results from my backup hosts (which back up customer data).

Type       Perc     Disk Usage   Uncompressed Referenced
TOTAL       64%       68G         105G         1.2T
none       100%       24G          24G         434G
zlib        54%       43G          80G         797G
Type       Perc     Disk Usage   Uncompressed Referenced
TOTAL       74%       91G         123G         992G
none       100%       59G          59G         599G
lzo         50%       32G          63G         393G
Type       Perc     Disk Usage   Uncompressed Referenced
TOTAL       73%       16G          22G         459G
none       100%       12G          12G         269G
lzo         40%      4.1G          10G         190G
Type       Perc     Disk Usage   Uncompressed Referenced
TOTAL       71%      105G         148G         1.9T
none       100%       70G          70G         910G
zlib        40%       24G          60G         1.0T
lzo         58%       10G          17G          17G

So that’s 398G that takes up 280G, a 29.6% reduction.

The “none” type is incompressible files such as media that’s already compressed. I started off with lzo compression but I’m switching to zlib now as it compresses more and this data is rarely accessed so I’m not too concerned about performance. I need newer kernels on these before I can try zstd.

I’ve had serious concerns about btrfs before based on issues I’ve had using it at home, but these were mostly around multiple device usage. Here they get a single block device that has redundancy underneath so the only remotely interesting thing that btrfs is doing here is the compression.

Might try some offline deduplication next.