# Writing to 2 files that share the duplicate blocks. # The dedupe working set is spread uniformly such that when # each of the jobs choose to perform a dedup operation they will # regenerate a buffer from the global space. # If you test the dedup ratio on either file by itself the result # is likely lower than if you test the ratio of the two files combined. # # Use `./t/fio-dedupe -C 1 -c 1 -b 4096` to test the total # data reduction ratio. # # # Full example of test: # $ ./fio ./examples/dedupe-global.fio # # Checking ratio on a and b individually: # $ ./t/fio-dedupe a.0.0 -C 1 -c 1 -b 4096 # # $ Extents=25600, Unique extents=16817 Duplicated extents=5735 # $ De-dupe ratio: 1:0.52 # $ De-dupe working set at least: 22.40% # $ Fio setting: dedupe_percentage=34 # $ Unique capacity 33MB # # ./t/fio-dedupe b.0.0 -C 1 -c 1 -b 4096 # $ Extents=25600, Unique extents=17009 Duplicated extents=5636 # $ De-dupe ratio: 1:0.51 # $ De-dupe working set at least: 22.02% # $ Fio setting: dedupe_percentage=34 # $ Unique capacity 34MB # # Combining files: # $ cat a.0.0 > c.0.0 # $ cat b.0.0 >> c.0.0 # # Checking data reduction ratio on combined file: # $ ./t/fio-dedupe c.0.0 -C 1 -c 1 -b 4096 # $ Extents=51200, Unique extents=25747 Duplicated extents=11028 # $ De-dupe ratio: 1:0.99 # $ De-dupe working set at least: 21.54% # $ Fio setting: dedupe_percentage=50 # $ Unique capacity 51MB # [global] ioengine=libaio iodepth=256 size=100m dedupe_mode=working_set dedupe_global=1 dedupe_percentage=50 blocksize=4k rw=write buffer_compress_percentage=50 dedupe_working_set_percentage=50 [a] [b]