On 4 March 2013 14:27, Jens Axboe <axboe@xxxxxxxxx> wrote: > On Mon, Mar 04 2013, Gavin Martin wrote: >> Hi, >> >> I'm trying to setup a job file that tests interleaved data, so in >> theory writing 256K blocks with a gap of 256K in between, the end >> results is that I would like to write extra data into the gaps and >> make sure it is not corrupting neighbouring areas. >> >> But I'm having a problem with the first part. >> >> Here is the jobfile:- >> >> [global] >> ioengine=libaio >> direct=1 >> filename=/dev/sdb >> verify=meta >> verify_backlog=1 >> verify_dump=1 >> verify_fatal=1 >> stonewall >> >> [Job 2] >> name=SeqWrite256K >> description=Sequential Write with 1M Bands (256K) >> rw=write:1M >> bs=256K >> do_verify=0 >> verify_pattern=0x33333333 >> size=1G >> >> [Job 4] >> name=SeqVerify256K >> description=Sequential Read/Verify from Sequential Write (256K) >> rw=read:1M >> bs=256K >> do_verify=1 >> verify_pattern=0x33333333 >> size=1G >> >> There seems to be a bug (or maybe by design) when using the 'size=' >> variable. It seems to count the gaps (1M) within the size of 1G, but >> only on the write, the reads seems to report the IO transferred as 1G >> >> Here is the status of the runs:- >> >> Run status group 0 (all jobs): >> WRITE: io=209920KB, aggrb=34039KB/s, minb=34039KB/s, maxb=34039KB/s, >> mint=6167msec, maxt=6167msec >> >> Run status group 1 (all jobs): >> READ: io=1025.0MB, aggrb=36759KB/s, minb=36759KB/s, maxb=36759KB/s, >> mint=28553msec, maxt=28553msec >> >> And you can see the Write IO is a lot lower than the Read IO, even >> though I have asked it to cover the same disk space. >> >> It could be that this is by design and it is my jobfile that is not >> setup correctly, has anybody tried something like this before? > > They should behave identically - if they don't, then that is a bug. I > will take a look at this tomorrow. > > -- > Jens Axboe > Thanks Jens, I'm not sure if interleaved is the right term, I suppose could also be called testing bands? I've just repeated using size=1% in case it was an issue with stating a GB size, but it is still the same. I was also using fio-2.0.14 so have just grabbed the latest from Git (fio-2.0.14-23-g9c63) and it exhibits the same issue. Regards, -- ------------------------------ For additional information including the registered office and the treatment of Xyratex confidential information please visit www.xyratex.com ------------------------------ -- To unsubscribe from this list: send the line "unsubscribe fio" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
