mathieu@berlin ~$ fio --randrepeat=1 --ioengine=libaio --direct=1 --gtod_reduce=1 --name=test --filename=/var/cache/test --bs=4k --iodepth=64 --size=4G --readwrite=randrw --rwmixread=75 test: (g=0): rw=randrw, bs=(R) 4096B-4096B, (W) 4096B-4096B, (T) 4096B-4096B, ioengine=libaio, iodepth=64 fio-3.28 Starting 1 process test: Laying out IO file (1 file / 4096MiB) fio: pid=0, err=13/file:filesetup.c:174, func=open, error=Permission denied Run status group 0 (all jobs): mathieu@berlin ~$ sudo fio --randrepeat=1 --ioengine=libaio --direct=1 --gtod_reduce=1 --name=test --filename=/var/cache/test --bs=4k --iodepth=64 --size=4G --readwrite=randrw --rwmixread=75 Password: test: (g=0): rw=randrw, bs=(R) 4096B-4096B, (W) 4096B-4096B, (T) 4096B-4096B, ioengine=libaio, iodepth=64 fio-3.28 Starting 1 process test: Laying out IO file (1 file / 4096MiB) Jobs: 1 (f=1): [m(1)][100.0%][r=6610KiB/s,w=2190KiB/s][r=1652,w=547 IOPS][eta 00m:00s] test: (groupid=0, jobs=1): err= 0: pid=49274: Fri Dec 17 11:30:38 2021 read: IOPS=2423, BW=9695KiB/s (9927kB/s)(3070MiB/324270msec) bw ( KiB/s): min= 2392, max=17808, per=100.00%, avg=9704.06, stdev=2476.08, samples=648 iops : min= 598, max= 4452, avg=2425.92, stdev=619.02, samples=648 write: IOPS=809, BW=3240KiB/s (3318kB/s)(1026MiB/324270msec); 0 zone resets bw ( KiB/s): min= 1080, max= 5968, per=100.00%, avg=3243.27, stdev=833.97, samples=648 iops : min= 270, max= 1492, avg=810.71, stdev=208.49, samples=648 cpu : usr=0.55%, sys=2.84%, ctx=1004749, majf=0, minf=129 IO depths : 1=0.1%, 2=0.1%, 4=0.1%, 8=0.1%, 16=0.1%, 32=0.1%, >=64=100.0% 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=0.1%, >=64=0.0% issued rwts: total=785920,262656,0,0 short=0,0,0,0 dropped=0,0,0,0 latency : target=0, window=0, percentile=100.00%, depth=64 Run status group 0 (all jobs): READ: bw=9695KiB/s (9927kB/s), 9695KiB/s-9695KiB/s (9927kB/s-9927kB/s), io=3070MiB (3219MB), run=324270-324270msec WRITE: bw=3240KiB/s (3318kB/s), 3240KiB/s-3240KiB/s (3318kB/s-3318kB/s), io=1026MiB (1076MB), run=324270-324270msec Disk stats (read/write): sdb: ios=790930/270846, merge=2539/10683, ticks=21982026/264629, in_queue=22246666, util=100.00%