fio fdatasync=

baseline_rw.fio

[global]
ioengine=psync
direct=1
filename=/mnt/disks/localssd/test-file
time_based
runtime=300
size=2000G
refill_buffers

[writer]
rw=write
bs=128k
iodepth=1
numjobs=1

[reader]
rw=randread
bs=128k
iodepth=1
numjobs=4

baseline_rw.txt

writer: (g=0): rw=write, bs=(R) 128KiB-128KiB, (W) 128KiB-128KiB, (T) 128KiB-128KiB, ioengine=psync, iodepth=1
reader: (g=0): rw=randread, bs=(R) 128KiB-128KiB, (W) 128KiB-128KiB, (T) 128KiB-128KiB, ioengine=psync, iodepth=1
...
fio-3.33
Starting 5 processes

writer: (groupid=0, jobs=1): err= 0: pid=14988: Tue Feb 24 03:52:34 2026
  write: IOPS=6312, BW=789MiB/s (827MB/s)(231GiB/300001msec); 0 zone resets
    clat (usec): min=40, max=1507, avg=146.82, stdev=237.01
     lat (usec): min=40, max=1507, avg=146.87, stdev=237.01
    clat percentiles (usec):
     |  1.00th=[   42],  5.00th=[   43], 10.00th=[   44], 20.00th=[   46],
     | 30.00th=[   47], 40.00th=[   47], 50.00th=[   47], 60.00th=[   48],
     | 70.00th=[   48], 80.00th=[   57], 90.00th=[  486], 95.00th=[  840],
     | 99.00th=[  988], 99.50th=[  996], 99.90th=[ 1012], 99.95th=[ 1483],
     | 99.99th=[ 1483]
   bw (  KiB/s): min=751616, max=951552, per=100.00%, avg=808343.29, stdev=30777.55, samples=599
   iops        : min= 5872, max= 7434, avg=6315.18, stdev=240.45, samples=599
  lat (usec)   : 50=76.26%, 100=4.71%, 250=0.98%, 500=12.31%, 750=0.72%
  lat (usec)   : 1000=4.87%
  lat (msec)   : 2=0.16%
  cpu          : usr=8.35%, sys=3.26%, ctx=1893906, majf=0, minf=10
  IO depths    : 1=100.0%, 2=0.0%, 4=0.0%, 8=0.0%, 16=0.0%, 32=0.0%, >=64=0.0%
     submit    : 0=0.0%, 4=100.0%, 8=0.0%, 16=0.0%, 32=0.0%, 64=0.0%, >=64=0.0%
     complete  : 0=0.0%, 4=100.0%, 8=0.0%, 16=0.0%, 32=0.0%, 64=0.0%, >=64=0.0%
     issued rwts: total=0,1893869,0,0 short=0,0,0,0 dropped=0,0,0,0
     latency   : target=0, window=0, percentile=100.00%, depth=1
reader: (groupid=0, jobs=1): err= 0: pid=14989: Tue Feb 24 03:52:34 2026
  read: IOPS=4577, BW=572MiB/s (600MB/s)(168GiB/300001msec)
    clat (usec): min=73, max=2460, avg=218.11, stdev=204.70
     lat (usec): min=73, max=2460, avg=218.14, stdev=204.70
    clat percentiles (usec):
     |  1.00th=[   90],  5.00th=[   93], 10.00th=[   97], 20.00th=[  102],
     | 30.00th=[  110], 40.00th=[  119], 50.00th=[  133], 60.00th=[  149],
     | 70.00th=[  180], 80.00th=[  285], 90.00th=[  494], 95.00th=[  693],
     | 99.00th=[ 1012], 99.50th=[ 1057], 99.90th=[ 1303], 99.95th=[ 1467],
     | 99.99th=[ 1696]
   bw (  KiB/s): min=520704, max=641792, per=25.03%, avg=586073.93, stdev=17909.48, samples=599
   iops        : min= 4068, max= 5014, avg=4578.70, stdev=139.92, samples=599
  lat (usec)   : 100=15.16%, 250=62.33%, 500=12.81%, 750=5.32%, 1000=3.15%
  lat (msec)   : 2=1.22%, 4=0.01%
  cpu          : usr=0.55%, sys=2.66%, ctx=1373362, majf=0, minf=42
  IO depths    : 1=100.0%, 2=0.0%, 4=0.0%, 8=0.0%, 16=0.0%, 32=0.0%, >=64=0.0%
     submit    : 0=0.0%, 4=100.0%, 8=0.0%, 16=0.0%, 32=0.0%, 64=0.0%, >=64=0.0%
     complete  : 0=0.0%, 4=100.0%, 8=0.0%, 16=0.0%, 32=0.0%, 64=0.0%, >=64=0.0%
     issued rwts: total=1373299,0,0,0 short=0,0,0,0 dropped=0,0,0,0
     latency   : target=0, window=0, percentile=100.00%, depth=1
reader: (groupid=0, jobs=1): err= 0: pid=14990: Tue Feb 24 03:52:34 2026
  read: IOPS=4573, BW=572MiB/s (599MB/s)(167GiB/300001msec)
    clat (usec): min=73, max=2747, avg=218.31, stdev=204.49
     lat (usec): min=73, max=2747, avg=218.34, stdev=204.49
    clat percentiles (usec):
     |  1.00th=[   90],  5.00th=[   93], 10.00th=[   98], 20.00th=[  103],
     | 30.00th=[  110], 40.00th=[  119], 50.00th=[  133], 60.00th=[  149],
     | 70.00th=[  182], 80.00th=[  289], 90.00th=[  494], 95.00th=[  685],
     | 99.00th=[ 1012], 99.50th=[ 1057], 99.90th=[ 1319], 99.95th=[ 1483],
     | 99.99th=[ 1713]
   bw (  KiB/s): min=515840, max=634368, per=25.01%, avg=585524.30, stdev=17792.48, samples=599
   iops        : min= 4030, max= 4956, avg=4574.41, stdev=139.00, samples=599
  lat (usec)   : 100=14.44%, 250=63.03%, 500=12.85%, 750=5.34%, 1000=3.13%
  lat (msec)   : 2=1.22%, 4=0.01%
  cpu          : usr=0.53%, sys=2.80%, ctx=1372081, majf=0, minf=41
  IO depths    : 1=100.0%, 2=0.0%, 4=0.0%, 8=0.0%, 16=0.0%, 32=0.0%, >=64=0.0%
     submit    : 0=0.0%, 4=100.0%, 8=0.0%, 16=0.0%, 32=0.0%, 64=0.0%, >=64=0.0%
     complete  : 0=0.0%, 4=100.0%, 8=0.0%, 16=0.0%, 32=0.0%, 64=0.0%, >=64=0.0%
     issued rwts: total=1372003,0,0,0 short=0,0,0,0 dropped=0,0,0,0
     latency   : target=0, window=0, percentile=100.00%, depth=1
reader: (groupid=0, jobs=1): err= 0: pid=14991: Tue Feb 24 03:52:34 2026
  read: IOPS=4578, BW=572MiB/s (600MB/s)(168GiB/300001msec)
    clat (usec): min=73, max=2653, avg=218.05, stdev=204.45
     lat (usec): min=73, max=2653, avg=218.09, stdev=204.45
    clat percentiles (usec):
     |  1.00th=[   90],  5.00th=[   93], 10.00th=[   97], 20.00th=[  103],
     | 30.00th=[  110], 40.00th=[  119], 50.00th=[  133], 60.00th=[  149],
     | 70.00th=[  182], 80.00th=[  289], 90.00th=[  494], 95.00th=[  693],
     | 99.00th=[ 1012], 99.50th=[ 1057], 99.90th=[ 1319], 99.95th=[ 1467],
     | 99.99th=[ 1745]
   bw (  KiB/s): min=512256, max=634368, per=25.04%, avg=586211.86, stdev=18427.82, samples=599
   iops        : min= 4002, max= 4956, avg=4579.78, stdev=143.97, samples=599
  lat (usec)   : 100=14.97%, 250=62.50%, 500=12.87%, 750=5.30%, 1000=3.17%
  lat (msec)   : 2=1.19%, 4=0.01%
  cpu          : usr=0.63%, sys=2.66%, ctx=1373684, majf=0, minf=41
  IO depths    : 1=100.0%, 2=0.0%, 4=0.0%, 8=0.0%, 16=0.0%, 32=0.0%, >=64=0.0%
     submit    : 0=0.0%, 4=100.0%, 8=0.0%, 16=0.0%, 32=0.0%, 64=0.0%, >=64=0.0%
     complete  : 0=0.0%, 4=100.0%, 8=0.0%, 16=0.0%, 32=0.0%, 64=0.0%, >=64=0.0%
     issued rwts: total=1373576,0,0,0 short=0,0,0,0 dropped=0,0,0,0
     latency   : target=0, window=0, percentile=100.00%, depth=1
reader: (groupid=0, jobs=1): err= 0: pid=14992: Tue Feb 24 03:52:34 2026
  read: IOPS=4561, BW=570MiB/s (598MB/s)(167GiB/300001msec)
    clat (usec): min=73, max=2689, avg=218.89, stdev=204.47
     lat (usec): min=73, max=2689, avg=218.93, stdev=204.47
    clat percentiles (usec):
     |  1.00th=[   90],  5.00th=[   94], 10.00th=[   98], 20.00th=[  103],
     | 30.00th=[  110], 40.00th=[  119], 50.00th=[  133], 60.00th=[  149],
     | 70.00th=[  182], 80.00th=[  289], 90.00th=[  494], 95.00th=[  693],
     | 99.00th=[ 1012], 99.50th=[ 1057], 99.90th=[ 1303], 99.95th=[ 1467],
     | 99.99th=[ 1745]
   bw (  KiB/s): min=514304, max=630528, per=24.94%, avg=583991.38, stdev=17238.77, samples=599
   iops        : min= 4018, max= 4926, avg=4562.43, stdev=134.68, samples=599
  lat (usec)   : 100=13.75%, 250=63.60%, 500=12.93%, 750=5.36%, 1000=3.16%
  lat (msec)   : 2=1.19%, 4=0.01%
  cpu          : usr=0.70%, sys=2.74%, ctx=1368387, majf=0, minf=41
  IO depths    : 1=100.0%, 2=0.0%, 4=0.0%, 8=0.0%, 16=0.0%, 32=0.0%, >=64=0.0%
     submit    : 0=0.0%, 4=100.0%, 8=0.0%, 16=0.0%, 32=0.0%, 64=0.0%, >=64=0.0%
     complete  : 0=0.0%, 4=100.0%, 8=0.0%, 16=0.0%, 32=0.0%, 64=0.0%, >=64=0.0%
     issued rwts: total=1368326,0,0,0 short=0,0,0,0 dropped=0,0,0,0
     latency   : target=0, window=0, percentile=100.00%, depth=1

Run status group 0 (all jobs):
   READ: bw=2286MiB/s (2397MB/s), 570MiB/s-572MiB/s (598MB/s-600MB/s), io=670GiB (719GB), run=300001-300001msec
  WRITE: bw=789MiB/s (827MB/s), 789MiB/s-789MiB/s (827MB/s-827MB/s), io=231GiB (248GB), run=300001-300001msec

Disk stats (read/write):
    md0: ios=6504689/2235533, merge=0/0, ticks=1266400/274248, in_queue=1540648, util=99.99%, aggrios=1084484/372714, aggrmerge=15/4, aggrticks=211357/45874, aggrin_queue=257231, aggrutil=50.99%
  nvme3n1: ios=1084119/372710, merge=10/2, ticks=205655/43629, in_queue=249284, util=49.60%
  nvme6n1: ios=1084723/372712, merge=15/6, ticks=212148/46845, in_queue=258993, util=50.67%
  nvme2n1: ios=1084079/372709, merge=20/3, ticks=207558/45025, in_queue=252583, util=49.80%
  nvme5n1: ios=1085269/372709, merge=19/6, ticks=215311/48268, in_queue=263578, util=50.66%
  nvme1n1: ios=1083874/372730, merge=17/7, ticks=212162/44249, in_queue=256412, util=50.99%
  nvme4n1: ios=1084845/372717, merge=12/3, ticks=215309/47231, in_queue=262540, util=50.80%

baseline_wo.fio

[global]
ioengine=psync
direct=1
filename=/mnt/disks/localssd/test-file
time_based
runtime=300
size=2000G
refill_buffers

[writer]
rw=write
bs=128k
iodepth=1
numjobs=1

baseline_wo.txt

writer: (g=0): rw=write, bs=(R) 128KiB-128KiB, (W) 128KiB-128KiB, (T) 128KiB-128KiB, ioengine=psync, iodepth=1
fio-3.33
Starting 1 process

writer: (groupid=0, jobs=1): err= 0: pid=15033: Tue Feb 24 03:57:35 2026
  write: IOPS=16.0k, BW=2005MiB/s (2102MB/s)(587GiB/300001msec); 0 zone resets
    clat (usec): min=40, max=3066, avg=50.63, stdev=24.09
     lat (usec): min=40, max=3066, avg=50.68, stdev=24.09
    clat percentiles (usec):
     |  1.00th=[   42],  5.00th=[   42], 10.00th=[   42], 20.00th=[   44],
     | 30.00th=[   46], 40.00th=[   46], 50.00th=[   46], 60.00th=[   46],
     | 70.00th=[   46], 80.00th=[   47], 90.00th=[   49], 95.00th=[   84],
     | 99.00th=[  182], 99.50th=[  188], 99.90th=[  210], 99.95th=[  215],
     | 99.99th=[  219]
   bw (  MiB/s): min= 2001, max= 2026, per=100.00%, avg=2005.30, stdev= 1.97, samples=599
   iops        : min=16012, max=16210, avg=16042.38, stdev=15.76, samples=599
  lat (usec)   : 50=90.86%, 100=5.33%, 250=3.81%, 500=0.01%, 750=0.01%
  lat (usec)   : 1000=0.01%
  lat (msec)   : 4=0.01%
  cpu          : usr=21.24%, sys=7.27%, ctx=4811646, majf=0, minf=10
  IO depths    : 1=100.0%, 2=0.0%, 4=0.0%, 8=0.0%, 16=0.0%, 32=0.0%, >=64=0.0%
     submit    : 0=0.0%, 4=100.0%, 8=0.0%, 16=0.0%, 32=0.0%, 64=0.0%, >=64=0.0%
     complete  : 0=0.0%, 4=100.0%, 8=0.0%, 16=0.0%, 32=0.0%, 64=0.0%, >=64=0.0%
     issued rwts: total=0,4811564,0,0 short=0,0,0,0 dropped=0,0,0,0
     latency   : target=0, window=0, percentile=100.00%, depth=1

Run status group 0 (all jobs):
  WRITE: bw=2005MiB/s (2102MB/s), 2005MiB/s-2005MiB/s (2102MB/s-2102MB/s), io=587GiB (631GB), run=300001-300001msec

Disk stats (read/write):
    md0: ios=0/5619219, merge=0/0, ticks=0/231168, in_queue=231168, util=69.93%, aggrios=0/936877, aggrmerge=0/11, aggrticks=0/39060, aggrin_queue=39061, aggrutil=17.87%
  nvme3n1: ios=0/936869, merge=0/9, ticks=0/36580, in_queue=36581, util=13.51%
  nvme6n1: ios=0/936873, merge=0/12, ticks=0/34469, in_queue=34469, util=10.61%
  nvme2n1: ios=0/936874, merge=0/10, ticks=0/36434, in_queue=36434, util=12.71%
  nvme5n1: ios=0/936871, merge=0/12, ticks=0/38680, in_queue=38680, util=12.76%
  nvme1n1: ios=0/936897, merge=0/13, ticks=0/37852, in_queue=37852, util=12.58%
  nvme4n1: ios=0/936881, merge=0/10, ticks=0/50350, in_queue=50350, util=17.87%

fdatasync_rw.fio

[global]
ioengine=psync
direct=1
filename=/mnt/disks/localssd/test-file
time_based
runtime=300
size=2000G
refill_buffers

[writer]
rw=write
bs=128k
iodepth=1
numjobs=1
fdatasync=1

[reader]
rw=randread
bs=128k
iodepth=1
numjobs=4

fdatasync_rw.txt

writer: (g=0): rw=write, bs=(R) 128KiB-128KiB, (W) 128KiB-128KiB, (T) 128KiB-128KiB, ioengine=psync, iodepth=1
reader: (g=0): rw=randread, bs=(R) 128KiB-128KiB, (W) 128KiB-128KiB, (T) 128KiB-128KiB, ioengine=psync, iodepth=1
...
fio-3.33
Starting 5 processes

writer: (groupid=0, jobs=1): err= 0: pid=14898: Tue Feb 24 03:42:34 2026
  write: IOPS=6329, BW=791MiB/s (830MB/s)(232GiB/300001msec); 0 zone resets
    clat (usec): min=41, max=1503, avg=143.07, stdev=232.44
     lat (usec): min=41, max=1503, avg=143.12, stdev=232.44
    clat percentiles (usec):
     |  1.00th=[   42],  5.00th=[   43], 10.00th=[   44], 20.00th=[   46],
     | 30.00th=[   47], 40.00th=[   47], 50.00th=[   47], 60.00th=[   48],
     | 70.00th=[   49], 80.00th=[   57], 90.00th=[  482], 95.00th=[  506],
     | 99.00th=[  988], 99.50th=[  988], 99.90th=[ 1004], 99.95th=[ 1483],
     | 99.99th=[ 1483]
   bw (  KiB/s): min=760576, max=999680, per=100.00%, avg=810431.47, stdev=28122.42, samples=599
   iops        : min= 5942, max= 7810, avg=6331.50, stdev=219.71, samples=599
  lat (usec)   : 50=75.31%, 100=5.86%, 250=1.36%, 500=12.18%, 750=0.38%
  lat (usec)   : 1000=4.79%
  lat (msec)   : 2=0.11%
  fsync/fdatasync/sync_file_range:
    sync (nsec): min=2544, max=23426, avg=2950.89, stdev=297.46
    sync percentiles (nsec):
     |  1.00th=[ 2704],  5.00th=[ 2768], 10.00th=[ 2800], 20.00th=[ 2832],
     | 30.00th=[ 2864], 40.00th=[ 2896], 50.00th=[ 2928], 60.00th=[ 2928],
     | 70.00th=[ 2960], 80.00th=[ 3024], 90.00th=[ 3088], 95.00th=[ 3152],
     | 99.00th=[ 3536], 99.50th=[ 4832], 99.90th=[ 6880], 99.95th=[ 7200],
     | 99.99th=[ 9664]
  cpu          : usr=8.20%, sys=4.45%, ctx=3797728, majf=0, minf=13
  IO depths    : 1=200.0%, 2=0.0%, 4=0.0%, 8=0.0%, 16=0.0%, 32=0.0%, >=64=0.0%
     submit    : 0=0.0%, 4=100.0%, 8=0.0%, 16=0.0%, 32=0.0%, 64=0.0%, >=64=0.0%
     complete  : 0=0.0%, 4=100.0%, 8=0.0%, 16=0.0%, 32=0.0%, 64=0.0%, >=64=0.0%
     issued rwts: total=0,1898826,0,0 short=1898825,0,0,0 dropped=0,0,0,0
     latency   : target=0, window=0, percentile=100.00%, depth=1
reader: (groupid=0, jobs=1): err= 0: pid=14899: Tue Feb 24 03:42:34 2026
  read: IOPS=4573, BW=572MiB/s (599MB/s)(167GiB/300001msec)
    clat (usec): min=73, max=4350, avg=218.29, stdev=207.76
     lat (usec): min=73, max=4350, avg=218.33, stdev=207.76
    clat percentiles (usec):
     |  1.00th=[   90],  5.00th=[   93], 10.00th=[   97], 20.00th=[  102],
     | 30.00th=[  109], 40.00th=[  117], 50.00th=[  130], 60.00th=[  149],
     | 70.00th=[  182], 80.00th=[  285], 90.00th=[  494], 95.00th=[  701],
     | 99.00th=[ 1012], 99.50th=[ 1074], 99.90th=[ 1418], 99.95th=[ 1532],
     | 99.99th=[ 2073]
   bw (  KiB/s): min=508152, max=636672, per=25.04%, avg=585547.63, stdev=17206.73, samples=599
   iops        : min= 3969, max= 4974, avg=4574.59, stdev=134.43, samples=599
  lat (usec)   : 100=15.65%, 250=61.80%, 500=12.88%, 750=5.23%, 1000=3.18%
  lat (msec)   : 2=1.25%, 4=0.01%, 10=0.01%
  cpu          : usr=0.62%, sys=2.70%, ctx=1372105, majf=0, minf=43
  IO depths    : 1=100.0%, 2=0.0%, 4=0.0%, 8=0.0%, 16=0.0%, 32=0.0%, >=64=0.0%
     submit    : 0=0.0%, 4=100.0%, 8=0.0%, 16=0.0%, 32=0.0%, 64=0.0%, >=64=0.0%
     complete  : 0=0.0%, 4=100.0%, 8=0.0%, 16=0.0%, 32=0.0%, 64=0.0%, >=64=0.0%
     issued rwts: total=1372042,0,0,0 short=0,0,0,0 dropped=0,0,0,0
     latency   : target=0, window=0, percentile=100.00%, depth=1
reader: (groupid=0, jobs=1): err= 0: pid=14900: Tue Feb 24 03:42:34 2026
  read: IOPS=4557, BW=570MiB/s (597MB/s)(167GiB/300001msec)
    clat (usec): min=72, max=4312, avg=219.03, stdev=208.44
     lat (usec): min=72, max=4312, avg=219.07, stdev=208.44
    clat percentiles (usec):
     |  1.00th=[   90],  5.00th=[   93], 10.00th=[   97], 20.00th=[  102],
     | 30.00th=[  109], 40.00th=[  118], 50.00th=[  131], 60.00th=[  149],
     | 70.00th=[  182], 80.00th=[  289], 90.00th=[  498], 95.00th=[  701],
     | 99.00th=[ 1012], 99.50th=[ 1074], 99.90th=[ 1434], 99.95th=[ 1549],
     | 99.99th=[ 2073]
   bw (  KiB/s): min=511486, max=620544, per=24.96%, avg=583565.89, stdev=15934.26, samples=599
   iops        : min= 3995, max= 4848, avg=4559.11, stdev=124.49, samples=599
  lat (usec)   : 100=15.40%, 250=61.91%, 500=12.94%, 750=5.27%, 1000=3.20%
  lat (msec)   : 2=1.26%, 4=0.01%, 10=0.01%
  cpu          : usr=0.67%, sys=2.66%, ctx=1367481, majf=0, minf=43
  IO depths    : 1=100.0%, 2=0.0%, 4=0.0%, 8=0.0%, 16=0.0%, 32=0.0%, >=64=0.0%
     submit    : 0=0.0%, 4=100.0%, 8=0.0%, 16=0.0%, 32=0.0%, 64=0.0%, >=64=0.0%
     complete  : 0=0.0%, 4=100.0%, 8=0.0%, 16=0.0%, 32=0.0%, 64=0.0%, >=64=0.0%
     issued rwts: total=1367387,0,0,0 short=0,0,0,0 dropped=0,0,0,0
     latency   : target=0, window=0, percentile=100.00%, depth=1
reader: (groupid=0, jobs=1): err= 0: pid=14901: Tue Feb 24 03:42:34 2026
  read: IOPS=4572, BW=572MiB/s (599MB/s)(167GiB/300001msec)
    clat (usec): min=73, max=3917, avg=218.34, stdev=207.82
     lat (usec): min=73, max=3917, avg=218.37, stdev=207.82
    clat percentiles (usec):
     |  1.00th=[   90],  5.00th=[   93], 10.00th=[   97], 20.00th=[  102],
     | 30.00th=[  109], 40.00th=[  117], 50.00th=[  130], 60.00th=[  149],
     | 70.00th=[  182], 80.00th=[  289], 90.00th=[  494], 95.00th=[  701],
     | 99.00th=[ 1012], 99.50th=[ 1074], 99.90th=[ 1418], 99.95th=[ 1532],
     | 99.99th=[ 2089]
   bw (  KiB/s): min=504304, max=633088, per=25.04%, avg=585418.12, stdev=17750.39, samples=599
   iops        : min= 3939, max= 4946, avg=4573.58, stdev=138.68, samples=599
  lat (usec)   : 100=15.61%, 250=61.83%, 500=12.88%, 750=5.24%, 1000=3.18%
  lat (msec)   : 2=1.25%, 4=0.01%
  cpu          : usr=0.66%, sys=2.66%, ctx=1371836, majf=0, minf=42
  IO depths    : 1=100.0%, 2=0.0%, 4=0.0%, 8=0.0%, 16=0.0%, 32=0.0%, >=64=0.0%
     submit    : 0=0.0%, 4=100.0%, 8=0.0%, 16=0.0%, 32=0.0%, 64=0.0%, >=64=0.0%
     complete  : 0=0.0%, 4=100.0%, 8=0.0%, 16=0.0%, 32=0.0%, 64=0.0%, >=64=0.0%
     issued rwts: total=1371785,0,0,0 short=0,0,0,0 dropped=0,0,0,0
     latency   : target=0, window=0, percentile=100.00%, depth=1
reader: (groupid=0, jobs=1): err= 0: pid=14902: Tue Feb 24 03:42:34 2026
  read: IOPS=4564, BW=571MiB/s (598MB/s)(167GiB/300001msec)
    clat (usec): min=72, max=4010, avg=218.73, stdev=208.69
     lat (usec): min=72, max=4010, avg=218.77, stdev=208.69
    clat percentiles (usec):
     |  1.00th=[   90],  5.00th=[   93], 10.00th=[   97], 20.00th=[  102],
     | 30.00th=[  109], 40.00th=[  117], 50.00th=[  130], 60.00th=[  149],
     | 70.00th=[  182], 80.00th=[  289], 90.00th=[  498], 95.00th=[  701],
     | 99.00th=[ 1012], 99.50th=[ 1074], 99.90th=[ 1434], 99.95th=[ 1549],
     | 99.99th=[ 2057]
   bw (  KiB/s): min=496865, max=623104, per=24.99%, avg=584406.07, stdev=16949.01, samples=599
   iops        : min= 3881, max= 4868, avg=4565.67, stdev=132.42, samples=599
  lat (usec)   : 100=16.27%, 250=61.09%, 500=12.87%, 750=5.32%, 1000=3.16%
  lat (msec)   : 2=1.28%, 4=0.01%, 10=0.01%
  cpu          : usr=0.64%, sys=2.59%, ctx=1369372, majf=0, minf=42
  IO depths    : 1=100.0%, 2=0.0%, 4=0.0%, 8=0.0%, 16=0.0%, 32=0.0%, >=64=0.0%
     submit    : 0=0.0%, 4=100.0%, 8=0.0%, 16=0.0%, 32=0.0%, 64=0.0%, >=64=0.0%
     complete  : 0=0.0%, 4=100.0%, 8=0.0%, 16=0.0%, 32=0.0%, 64=0.0%, >=64=0.0%
     issued rwts: total=1369292,0,0,0 short=0,0,0,0 dropped=0,0,0,0
     latency   : target=0, window=0, percentile=100.00%, depth=1

Run status group 0 (all jobs):
   READ: bw=2284MiB/s (2394MB/s), 570MiB/s-572MiB/s (597MB/s-599MB/s), io=669GiB (718GB), run=300001-300001msec
  WRITE: bw=791MiB/s (830MB/s), 791MiB/s-791MiB/s (830MB/s-830MB/s), io=232GiB (249GB), run=300001-300001msec

Disk stats (read/write):
    md0: ios=6496647/2241711, merge=0/0, ticks=1265776/267984, in_queue=1533760, util=99.99%, aggrios=1083157/373747, aggrmerge=15/4, aggrticks=211179/44812, aggrin_queue=255991, aggrutil=51.09%
  nvme3n1: ios=1082789/373740, merge=10/2, ticks=204528/42326, in_queue=246855, util=49.51%
  nvme6n1: ios=1083366/373745, merge=15/6, ticks=214018/46331, in_queue=260349, util=51.00%
  nvme2n1: ios=1082795/373742, merge=20/3, ticks=204654/42825, in_queue=247479, util=49.58%
  nvme5n1: ios=1083981/373739, merge=19/6, ticks=216342/47867, in_queue=264209, util=50.89%
  nvme1n1: ios=1082495/373764, merge=17/6, ticks=216045/44892, in_queue=260937, util=51.09%
  nvme4n1: ios=1083517/373756, merge=12/6, ticks=211490/44631, in_queue=256122, util=50.59%

fdatasync_wo.fio

[global]
ioengine=psync
direct=1
filename=/mnt/disks/localssd/test-file
time_based
runtime=300
size=2000G
refill_buffers

[writer]
rw=write
bs=128k
iodepth=1
numjobs=1
fdatasync=1

fdatasync_wo.txt

writer: (g=0): rw=write, bs=(R) 128KiB-128KiB, (W) 128KiB-128KiB, (T) 128KiB-128KiB, ioengine=psync, iodepth=1
fio-3.33
Starting 1 process

writer: (groupid=0, jobs=1): err= 0: pid=14939: Tue Feb 24 03:47:34 2026
  write: IOPS=16.1k, BW=2010MiB/s (2108MB/s)(589GiB/300001msec); 0 zone resets
    clat (usec): min=40, max=3890, avg=47.56, stdev=11.20
     lat (usec): min=40, max=3890, avg=47.61, stdev=11.20
    clat percentiles (usec):
     |  1.00th=[   42],  5.00th=[   42], 10.00th=[   42], 20.00th=[   44],
     | 30.00th=[   45], 40.00th=[   46], 50.00th=[   46], 60.00th=[   46],
     | 70.00th=[   47], 80.00th=[   47], 90.00th=[   49], 95.00th=[   58],
     | 99.00th=[  113], 99.50th=[  118], 99.90th=[  125], 99.95th=[  126],
     | 99.99th=[  133]
   bw (  MiB/s): min= 2004, max= 2032, per=100.00%, avg=2010.55, stdev= 1.00, samples=599
   iops        : min=16038, max=16256, avg=16084.43, stdev= 8.00, samples=599
  lat (usec)   : 50=91.41%, 100=6.68%, 250=1.91%, 500=0.01%
  lat (msec)   : 4=0.01%
  fsync/fdatasync/sync_file_range:
    sync (nsec): min=2470, max=55435, avg=2708.96, stdev=191.03
    sync percentiles (nsec):
     |  1.00th=[ 2576],  5.00th=[ 2608], 10.00th=[ 2608], 20.00th=[ 2640],
     | 30.00th=[ 2672], 40.00th=[ 2672], 50.00th=[ 2704], 60.00th=[ 2704],
     | 70.00th=[ 2736], 80.00th=[ 2768], 90.00th=[ 2800], 95.00th=[ 2832],
     | 99.00th=[ 2992], 99.50th=[ 3120], 99.90th=[ 5856], 99.95th=[ 6560],
     | 99.99th=[ 8032]
  cpu          : usr=20.23%, sys=10.68%, ctx=9648364, majf=0, minf=12
  IO depths    : 1=200.0%, 2=0.0%, 4=0.0%, 8=0.0%, 16=0.0%, 32=0.0%, >=64=0.0%
     submit    : 0=0.0%, 4=100.0%, 8=0.0%, 16=0.0%, 32=0.0%, 64=0.0%, >=64=0.0%
     complete  : 0=0.0%, 4=100.0%, 8=0.0%, 16=0.0%, 32=0.0%, 64=0.0%, >=64=0.0%
     issued rwts: total=0,4824098,0,0 short=4824097,0,0,0 dropped=0,0,0,0
     latency   : target=0, window=0, percentile=100.00%, depth=1

Run status group 0 (all jobs):
  WRITE: bw=2010MiB/s (2108MB/s), 2010MiB/s-2010MiB/s (2108MB/s-2108MB/s), io=589GiB (632GB), run=300001-300001msec

Disk stats (read/write):
    md0: ios=0/5634895, merge=0/0, ticks=0/218748, in_queue=218748, util=65.55%, aggrios=0/939488, aggrmerge=0/11, aggrticks=0/36708, aggrin_queue=36708, aggrutil=15.79%
  nvme3n1: ios=0/939484, merge=0/9, ticks=0/35726, in_queue=35725, util=12.83%
  nvme6n1: ios=0/939484, merge=0/12, ticks=0/34583, in_queue=34583, util=11.53%
  nvme2n1: ios=0/939484, merge=0/10, ticks=0/36119, in_queue=36119, util=12.90%
  nvme5n1: ios=0/939483, merge=0/12, ticks=0/36031, in_queue=36032, util=11.46%
  nvme1n1: ios=0/939507, merge=0/13, ticks=0/35095, in_queue=35096, util=11.20%
  nvme4n1: ios=0/939491, merge=0/10, ticks=0/42697, in_queue=42697, util=15.79%