Like suggested in https://askubuntu.com/a/991311 I tested the read speed of a 2.5" spinning hard drive on a TrueNAS/FreeBSD system.

For "Sequential READ speed with big blocks":

fio --name TEST --eta-newline=5s --filename=fio-tempfile.dat --rw=read --size=500m --io_size=10g --blocksize=1024k --ioengine=posixaio --fsync=10000 --iodepth=32 --direct=1 --numjobs=1 --runtime=60 --group_reporting

I got 8037 MB/s.

I don’t believe this.

I did replace liaio with posixaio, do I need another engine?

1 Answer 1


I think you are testing the speed of your system's filesystem cache because you are only fsyncing every 10000 I/Os (so that's every 9GBytes). Does your speed change if you use you choose use the direct=1 option?

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.