Hello all, I have a 30TB drive and I am running into an issue with random writes. I went through this thread : https://www.spinics.net/lists/fio/msg06294.html that seems to be fixed already. I see the same issue with random reads as well. So not sure what is the issue here in my case; any help is greatly appreciated. Read Capacity results: Protection: prot_en=1, p_type=1, p_i_exponent=0 [type 2 protection] Logical block provisioning: lbpme=1, lbprz=1 Last logical block address=58781073407 (0xdaf9fffff), Number of logical blocks=58781073408 Logical block length=512 bytes Logical blocks per physical block exponent=3 [so physical block length=4096 bytes] Lowest aligned logical block address=0 Hence: Device size: 30095909584896 bytes, 2.87017e+007 MiB, 30095.9 GB C:\Program Files (x86)\fio>fio --ioengine=windowsaio --group_reporting --direct=1 --size=100% --bs=4K --thread --filename=\\.\PhysicalDrive1 --name=precond --rw=randwrite --iodepth=1 --numjobs=1 --debug=io,random fio: set debug option io fio: set debug option random precond: (g=0): rw=randwrite, bs=(R) 4096B-4096B, (W) 4096B-4096B, (T) 4096B-4096B, ioengine=windowsaio, iodepth=1 fio-3.6 Starting 1 thread fio: file \\.\PhysicalDrive1 exceeds 32-bit tausworthe random generator. fio: Switching to tausworthe64. Use the random_generator= option to get rid of this warning. io 3372 drop page cache \\.\PhysicalDrive1 random 3372 off rand 259043585 io 3372 fill: io_u 0A458780: off=0x1a6a158f000,len=0x1000,ddir=1,file=\\.\PhysicalDrive1 io 3372 prep: io_u 0A458780: off=0x1a6a158f000,len=0x1000,ddir=1,file=\\.\PhysicalDrive1 io 3372 queue: io_u 0A458780: off=0x1a6a158f000,len=0x1000,ddir=1,file=\\.\PhysicalDrive1 io 3372 calling ->commit(), depth 1 io 3372 io_u_queued_complete: min=1 io 3372 getevents: 1 io 3372 complete: io_u 0A458780: off=0x1a6a158f000,len=0x1000,ddir=1,file=\\.\PhysicalDrive1 random 3372 off rand 3179521932 io 3372 fill: io_u 0A458780: off=0x144365e7d000,len=0x0,ddir=1,file=\\.\PhysicalDrive1 io 3372 get_io_u: zero buflen on 0A458780 io 3372 get_io_u failed io 3372 drop page cache \\.\PhysicalDrive1 random 3372 off rand 17311067694306724737 io 3372 fill: io_u 0A458780: off=0x19afd9012000,len=0x0,ddir=1,file=\\.\PhysicalDrive1 io 3372 get_io_u: zero buflen on 0A458780 io 3372 get_io_u failed precond: No I/O performed by windowsaio, perhaps try --debug=io option for details? io 3372 close ioengine windowsaio io 3372 free ioengine windowsaio precond: (groupid=0, jobs=1): err= 0: pid=3372: Sat Sep 15 13:58:46 2018 write: IOPS=15, BW=60.6KiB/s (62.1kB/s)(4096B/66msec) slat (nsec): min=832488, max=832488, avg=832488.00, stdev= 0.00 clat (nsec): min=790958, max=790958, avg=790958.00, stdev= 0.00 lat (nsec): min=1623.4k, max=1623.4k, avg=1623446.00, stdev= 0.00 clat percentiles (usec): | 1.00th=[ 791], 5.00th=[ 791], 10.00th=[ 791], 20.00th=[ 791], | 30.00th=[ 791], 40.00th=[ 791], 50.00th=[ 791], 60.00th=[ 791], | 70.00th=[ 791], 80.00th=[ 791], 90.00th=[ 791], 95.00th=[ 791], | 99.00th=[ 791], 99.50th=[ 791], 99.90th=[ 791], 99.95th=[ 791], | 99.99th=[ 791] lat (usec) : 1000=100.00% cpu : usr=0.00%, sys=0.00%, ctx=0, majf=0, minf=0 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=0,1,0,0 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=60.6KiB/s (62.1kB/s), 60.6KiB/s-60.6KiB/s (62.1kB/s-62.1kB/s), io=4096B (4096B), run=66-66msec io 3944 ioengine cpuio unregistered io 3944 ioengine mmap unregistered io 3944 ioengine sync unregistered io 3944 ioengine psync unregistered io 3944 ioengine vsync unregistered io 3944 ioengine null unregistered io 3944 ioengine net unregistered io 3944 ioengine ftruncate unregistered io 3944 ioengine filecreate unregistered io 3944 ioengine windowsaio unregistered C:\Program Files (x86)\fio> I don’t see this issue if I use bs=8K or I use ba=512,8K, etc. Thanks smitha
