n0derunner

Creating compressible data with fio.

Published: (Updated: ) in fio, , , , by .

Today I used fio to create some compressible data to test on my Nutanix nodes.  I ended up using the following fio params to get what I wanted.   buffer_compress_percentage=50 refill_buffers buffer_pattern=0xdeadbeef buffer_compress_percentage does what you’d expect and specifies how compressible the data is refill_buffers Is required to make the above compress percentage do what you’d […]

Specifying Drive letters with fio for Windows.

Published: (Updated: ) in fio, , , , by .

Simple fio file for using Drive letters on Windows. This will create a file called “fiofile” on the F:\ Drive in Windows.  Notice that the specification is “Driveletter” “Backslash” “Colon” “Filename” In fio terms we are “escaping” the “:” which fio traditionally uses as a file separator. [global] bs=1024k size=1G time_based runtime=30 rw=read direct=1 iodepth=8 […]

Multiple devices/jobs in fio

Published: (Updated: ) in fio, , by .

If your underlying filesystem/devices have different response times (e.g. some devices are cached – or are on SSD) and others are on spinning disk, then the behavior of fio can be quite different depending on how the fio config file is specified.  Typically there are two approaches 1) Have a single “job” that has multiple […]