Re: [Tcpreplay-users] Dedicated High Performance tcpreplay Box

[Aaron T. <syn...@gm...>]

On Mon, May 26, 2008 at 7:36 AM, William Cobau <co...@co...> wrote:
> Tcpreplay community,
>
> I am already successfully using tcpreplay for my testing activities. Our
> setup is rather simple with a Linux server (typically Redhat EL5) connected
> directly via 1000 B/T to the system under test. The linux server uses
> tcpreplay (presently v3.2.5, but we could/will upgrade to v3.3.x) to send
> previous captured data streams to the system under test. There is no need
> for tcprewrite or the other tools in the tcpreplay suite as the tcpreplay
> box is simulating a mirror port or a tap.
>
> We are trying to enhance our testing by increasing amount of data and the
> data rate. The data was captured at roughly 350 Mbps over 3 hours for 450
> Gbytes/1e9 packets.
>
> Has anyone built or bought a box that handles this data rate and volume? Any
> suggestions or comments would be welcome.

There are a number of "tcpreplay in a box" solutions out there:
http://www.simena.net/TrafficGenerator.htm
http://www.dejavunetwork.com/

I've never even touched either of those boxes, so don't consider this
an endorsement or anything like that.

But 350Mbps should be pretty doable with a decent HW RAID controller
(either 0 or 5 is probably the way to go) card and enough drives.
Finding the right bang for the buck is a bit more tricky.    Remember
tcpreplay is very sequential read heavy, so optimize for that, not
random access.

Anyways, spend your $$$ on RAID controller/disks and a good Intel
Pro/1000 based cards (all PCI-Express).   Not much multi-threading to
worry about so a single dual-core CPU is fine, but you'll want to get
a fast one.  With that much traffic, you won't be able to use the
tcpreplay cache option so you only need a few GB of RAM.

You might want to read the postgresql-performance (or any other DB
list) archives and see what RAID controllers do well for sequential
reads/writes.  DB people seem to spend the most time/effort tweaking
their disks which is what you need to do here.

-- 
Aaron Turner
http://synfin.net/
http://tcpreplay.synfin.net/ - Pcap editing & replay tools for Unix
They that can give up essential liberty to obtain a little temporary
safety deserve neither liberty nor safety. -- Benjamin Franklin