Hi all,
I am new to fio and I have some question about how to use fio that I can't find on google。
1.For read test fio will lay out a file for the test. how the file is generated? will the block size or rw mode effect the file?
Can I use 4m seq write test to generate file for the 4k rand read test as long as the file size is the same or larger than the read test and the filename matches?
If I ran fio on a block device(like /dev/sdb1),how would fio lay out data for read test?
In filesysterm i can change the filename to let fio lay out a new file,but I can't do that with a block device.
I did some test to find that if I do some write test on a block device then do read test if fio read beyond the data where write test has wrote,the result would be inaccurate(speed be much faster than it should be)
2.Fio can use filename and directory to set the where the test is performed. For multi-thread test fio will only generate one file in filename mode but many files if in directory mode.
If I want to test against a block device I can only use filename to tell fio where to perform the test
I can understand in directory mode that each thread will read or write to a file and if i increase the numjobs to increase thread number
the total filesize increased so the test will cost more time.
But in filename mode there is only one file and if I increase the numjobs to increase thread number the filesize won't change,
but the test still cost more time(I thought differernt thread would write or read different part of the file so the time cost would be smaller,but the test result showed that I am wrong), how each thread read or write to the same file?
for the same enviroment would the result be different for using filename or directory?which one would be more accurate?or It fully depend on how I want to simluate the workload?
Thanks
2018-01-10
lin.yunfan
--
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
