On Mon, Jan 13, 2020 at 12:04 AM Sitsofe Wheeler <sitsofe@xxxxxxxxx> wrote: > > On Fri, 10 Jan 2020 at 06:35, Elliott, Robert (Servers) <elliott@xxxxxxx> wrote: > > > > What are all those reads to LBA 3750748672? Something is looking > > for partition tables? > > > > You're using direct=1 so the page cache shouldn't be doing > > prefetching. > > If you scribble over the start of a disk that can trigger udev rules > to rescan partitions and maybe that is checking for a backup GPT... > > -- > Sitsofe | http://sucs.org/~sits/ If I issue "nvme write" that works : # echo "hello" | nvme write -s 0 -c 0 -y 64 -z 4096 --prinfo=0 /dev/nvme0n1 write: Success # nvme read /dev/nvme0n1 -s 0 --prinfo=0 -z 4096 -y 64 hello read: Success fio fails : # fio --filename=/dev/nvme0n1 --rw=write --ioengine=libaio --direct=1 --do_verify=0 --name=test --bs=4096 --number_ios=1 --offset=100M --debug=io fio: set debug option io test: (g=0): rw=write, bs=(R) 4096B-4096B, (W) 4096B-4096B, (T) 4096B-4096B, ioengine=libaio, iodepth=1 fio-3.7 Starting 1 process io 20252 drop page cache /dev/nvme0n1 io 20252 fill: io_u 0xb4cc80: off=0x6400000,len=0x1000,ddir=1,file=/dev/nvme0n1 io 20252 prep: io_u 0xb4cc80: off=0x6400000,len=0x1000,ddir=1,file=/dev/nvme0n1 io 20252 prep: io_u 0xb4cc80: ret=0 io 20252 queue: io_u 0xb4cc80: off=0x6400000,len=0x1000,ddir=1,file=/dev/nvme0n1 io 20252 calling ->commit(), depth 1 io 20252 io_u_queued_complete: min=1 io 20252 getevents: 1 io 20252 complete: io_u 0xb4cc80: off=0x6400000,len=0x1000,ddir=1,file=/dev/nvme0n1 fio: io_u error on file /dev/nvme0n1: Invalid or incomplete multibyte or wide character: write offset=104857600, buflen=4096 io 20252 io_u_queued_complete: min=0 io 20252 getevents: 0 test: No I/O performed by libaio, perhaps try --debug=io option for details? fio: pid=20252, err=84/file:io_u.c:1747, func=io_u error, error=Invalid or incomplete multibyte or wide character io 20252 close ioengine libaio io 20252 free ioengine libaio test: (groupid=0, jobs=1): err=84 (file:io_u.c:1747, func=io_u error, error=Invalid or incomplete multibyte or wide character): pid=20252: Fri Jan 17 13:13:52 2020 cpu : usr=0.00%, sys=0.00%, ctx=1, majf=0, minf=24 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=50.0%, 4=50.0%, 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) Thanks smitha
