SIO from NetApp is a great tool for this. So is iometer if you wanted something from a non vendor source, but netapp also releases the source to SIO, so it's pretty trustworthy a tool to me. But I do like iozone's excel graph output (you hearing that NetApp?).

SIO has an output of iops, and MB's per second. You can do threading, and differnt block sizes to better simulate the workload your current setup handles.

The first thing you have to do, and I always for get this, is create a file that's the size of, or larger, of the workload you are going to run sio against. In solaris you can just use mkfile, but for linux, I just do a quick dd.

dd if=/dev/zero of=/mnt/netapp/root/test_sio_file bs=1024k count=100

which creates a 100MB file.

Here's an example output, so you see what I'm talking about...

[golliher@admin.lab sio] sudo ./sio_ntap_freebsd 50 100 4k 20m 4 2 /mnt/netapp/root/test_sio_file Version: 3.00

SIO_NTAP: Inputs Read %: 50 Random %: 100 Block Size: 4096 File Size: 20971520 Secs: 4 Threads: 2 File(s): /mnt/netapp/root/test_sio_file Outputs IOPS: 162 KB/s: 647 IOs: 2763 Terminating threads ...[golliher@admin.lab sio]

You can see more examples of how to run it from the man page, and I recommend doing that. As you can see, my run had half reads, half writes of random 4K I/O's to a file I specifed. The test ran for 4 seconds with 2 threads and on only 20MB of the target file.

Hope that helps.... -Blake

ps, the readme is out of date for SIO, the Makefile has full support for freebsd os. Probably a little tweaking, and it'll run on MacOSX...

On 10/28/05, ChazzCRH (sent by Nabble.com) lists@nabble.com wrote:

We are considering replacing our current NFS server which is a Dell 6650 with Quad Xeon MP 2.7 procs, 12GB RAM, 4GB NICS running RHEL3 with a 3050 cluster.

We are running 7.2K SATA drives from Winchester Systems connected via an U320 SCSI to the Dell today and we would be running NetApp's 250GB SATA drives on the 3050 cluster.

NetApp posts IOPS as a performance metric but I am unable to find anything like that related to my Dell configuration so trying to figure out the performance gain and justifying the money we would be saving is becoming very tough. I can look at reads and writes per sec using IOSTAT on my Dell but I am not 100% sure its apples to apples compared to IOPS.

Can anyone shed some light on this for me?

Thanks !

-C

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