Re: Using fio with blkread data, example needed

John Rouillard wrote:
> Also does anybody have a sample config file to replay the block
> traces? I have a system that I want to test against with faster local
> disks and io bus than the original.

In command line terms you do something like this:

fio --ioengine=libaio --iodepth=64 --direct=1 --filename=/dev/sdb
--read_iolog=trace.bin --name=replay --do_verify=0

where trace.bin is a file that was produced by 'blkparse -d'.

> To follow up on that comment, here is what I am trying to do. I have a
> series of processes (8) that write to/read from a local disk. I am
> trying to get information about the disk access patterns so that I can
> use fio to simulate the same disk workload on an nfs mounted
> partition.
>
> As part of this, I would be tuning the client and server side to try
> to get the best throughput, so having a repeatable test case is
> critical.

Are you aware of nfsreplay? You'd need to do the initial run over NFS
rather than on a local disk, but otherwise it seems like a good fit.

<http://nfsreplay.sourceforge.net/>

-- 
Joshua Root,  jmr AT gelato.unsw.edu.au
http://www.gelato.unsw.edu.au