FYI, a simple sequential write comparison between the common filesystems.
For a newly created filesystem, btrfs is super fast! The interesting thing is,
btrfs performs best in the dirty_thresh=100M cases, rather than the 1G/8G cases.
btrfs also performs equally well in the 1dd, 2dd, 10dd, 100dd cases. However
the tests are blind to the possibility of long term fragmentation.
btrfs ext3 ext4 xfs
------------------------ ------------------------ ------------------------ ------------------------
56.55 -45.8% 30.66 -10.8% 50.42 -26.1% 41.76 thresh=1G/X-100dd-4k-8p-4096M-1024M:10-3.1.0-rc8-ioless6a+
56.11 -37.2% 35.24 +0.2% 56.23 -13.9% 48.34 thresh=1G/X-10dd-4k-8p-4096M-1024M:10-3.1.0-rc8-ioless6a+
56.21 -22.5% 43.58 +3.4% 58.12 -6.9% 52.36 thresh=1G/X-1dd-4k-8p-4096M-1024M:10-3.1.0-rc8-ioless6a+
58.23 -35.9% 37.34 -20.2% 46.45 -23.5% 44.53 thresh=100M/X-10dd-4k-8p-4096M-100M:10-3.1.0-rc8-ioless6a+
58.43 -23.9% 44.44 -3.1% 56.60 -4.4% 55.89 thresh=100M/X-1dd-4k-8p-4096M-100M:10-3.1.0-rc8-ioless6a+
58.53 -28.7% 41.70 -7.5% 54.14 -12.7% 51.11 thresh=100M/X-2dd-4k-8p-4096M-100M:10-3.1.0-rc8-ioless6a+
54.37 -40.8% 32.21 -34.6% 35.58 -42.9% 31.07 thresh=8M/X-10dd-4k-8p-4096M-8M:10-3.1.0-rc8-ioless6a+
56.12 -19.1% 45.37 +0.5% 56.39 -1.2% 55.44 thresh=8M/X-1dd-4k-8p-4096M-8M:10-3.1.0-rc8-ioless6a+
56.22 -22.3% 43.71 -8.8% 51.26 -15.4% 47.59 thresh=8M/X-2dd-4k-8p-4096M-8M:10-3.1.0-rc8-ioless6a+
510.77 -30.6% 354.27 -8.9% 465.19 -16.2% 428.07 TOTAL write_bw
Below is a more extensive run on virtually the same kernel.
In the thresh=8G case, ext4 performs noticeably better than others,
and the number of dd tasks is no longer relevant with big enough memory.
btrfs ext3 ext4 xfs
------------------------ ------------------------ ------------------------ ------------------------
92.89 -28.6% 66.36 +7.8% 100.10 -2.7% 90.41 thresh=8G/X-100dd-1M-32p-32768M-8192M:10-3.1.0-rc8-ioless6+
89.69 -19.7% 72.00 +18.7% 106.42 +2.2% 91.67 thresh=8G/X-10dd-1M-32p-32768M-8192M:10-3.1.0-rc8-ioless6+
92.26 -18.7% 75.01 +16.3% 107.26 +1.4% 93.51 thresh=8G/X-1dd-1M-32p-32768M-8192M:10-3.1.0-rc8-ioless6+
89.96 -16.8% 74.87 +20.7% 108.62 +3.1% 92.76 thresh=8G/X-2dd-1M-32p-32768M-8192M:10-3.1.0-rc8-ioless6+
note: the above 8G cases run on another test box!
60.29 -47.0% 31.96 -14.6% 51.47 -27.9% 43.44 thresh=1G/X-100dd-4k-8p-4096M-1024M:10-3.1.0-rc8-ioless6+
58.80 -38.5% 36.19 -4.4% 56.19 -15.3% 49.83 thresh=1G/X-10dd-4k-8p-4096M-1024M:10-3.1.0-rc8-ioless6+
58.53 -23.1% 45.03 -0.2% 58.41 -10.0% 52.70 thresh=1G/X-1dd-4k-8p-4096M-1024M:10-3.1.0-rc8-ioless6+
58.01 -35.0% 37.69 -4.1% 55.62 -12.4% 50.82 thresh=400M-300M/X-10dd-4k-8p-4096M-400M:300M-3.1.0-rc8-ioless6+
57.69 -26.0% 42.69 +1.8% 58.71 -2.4% 56.33 thresh=400M-300M/X-1dd-4k-8p-4096M-400M:300M-3.1.0-rc8-ioless6+
57.13 -32.4% 38.63 +2.5% 58.58 -6.8% 53.27 thresh=400M-300M/X-2dd-4k-8p-4096M-400M:300M-3.1.0-rc8-ioless6+
56.97 -33.3% 38.01 -3.2% 55.14 -9.3% 51.67 thresh=400M/X-10dd-4k-8p-4096M-400M:10-3.1.0-rc8-ioless6+
57.78 -22.3% 44.90 +0.6% 58.14 -0.7% 57.35 thresh=400M/X-1dd-4k-8p-4096M-400M:10-3.1.0-rc8-ioless6+
56.12 -27.3% 40.81 +2.4% 57.49 -4.9% 53.36 thresh=400M/X-2dd-4k-8p-4096M-400M:10-3.1.0-rc8-ioless6+
59.39 -36.0% 38.02 -20.0% 47.50 -24.4% 44.89 thresh=100M/X-10dd-4k-8p-4096M-100M:10-3.1.0-rc8-ioless6+
58.68 -23.0% 45.20 -0.9% 58.18 -1.1% 58.06 thresh=100M/X-1dd-4k-8p-4096M-100M:10-3.1.0-rc8-ioless6+
58.92 -27.9% 42.50 -5.3% 55.79 -11.8% 51.94 thresh=100M/X-2dd-4k-8p-4096M-100M:10-3.1.0-rc8-ioless6+
57.12 -41.1% 33.63 -36.0% 36.58 -43.6% 32.19 thresh=8M/X-10dd-4k-8p-4096M-8M:10-3.1.0-rc8-ioless6+
59.29 -18.5% 48.30 -3.3% 57.35 -5.8% 55.86 thresh=8M/X-1dd-4k-8p-4096M-8M:10-3.1.0-rc8-ioless6+
59.23 -21.0% 46.77 -10.8% 52.82 -17.3% 48.96 thresh=8M/X-2dd-4k-8p-4096M-8M:10-3.1.0-rc8-ioless6+
1238.75 -27.5% 898.56 +0.1% 1240.38 -8.9% 1129.01 TOTAL write_bw
Thanks,
Fengguang
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