after a comma, it will apply to writes only. In other words,
the format is either bs=read_and_write or bs=read,write.
bs=4k,8k will thus use 4k blocks for reads, and 8k blocks
- for writes.
+ for writes. If you only wish to set the write size, you
+ can do so by passing an empty read size - bs=,8k will set
+ 8k for writes and leave the read default value.
bsrange=irange Instead of giving a single block size, specify a range
and fio will mix the issued io block sizes. The issued