FreeBSD Performance

[David]

On Feb 27, 2011, at 4:43 PM, Robert Bonomi wrote:

>> From owner-freebsd-questions at freebsd.org  Sun Feb 27 14:54:09 2011
>> From: David <cyber366 at gmail.com>
>> Date: Sun, 27 Feb 2011 15:46:03 -0500
>> To: freebsd-questions at freebsd.org
>> Subject: FreeBSD Performance
>> 
>> Hello All:
>> 
>> I am curious... does anyone know of a reasonably priced commodity server 
>> capable of sourcing/sinking 10 Gbps of data from/to disk via 2 x 10 GE 
>> network interfaces? Any ideas on how hard this would be to do with 
>> FreeBSD?
>> 
>> I know of a proprietary linux-based system, but looking for open-source 
>> FreeBSD based system.

Thanks for the comments Robert...

> A lot depends on what you need to do with the data.

At the moment, I'm just looking to see if anyone has tried anything similar.
I have a detailed set of requirements/results, but wanted to keep things simple initially.
For now, let's just say there are two use cases:

1. Record 10 Gbps of data received from 2 10xGE cards onto hard disk array
2. Playback 10 Gbps of data out over 2 10xGE cards onto network.

>  Do you need just the 'contents' of the network packets -- i.e. are you
>  trying to send/recieve a single stream of data -- or do you need 
>  complete headers, augmented with timestamps, such that you can re-
>  construct/replay what was 'seen on the wire'?

Just contents is fine.

>  Is the box 'dedicated' to receiving (or sending), and does -nothing-else-
>  while that operation is in process? or do you need to sample the data in
>  real-time as well?

Dedicated.

>  Another question is _how_long_ you need to handle the 2x10gbit/sec of 
>  data. a few seconds? a few tens of seconds?  minutes? hours?

One hour (for now).

>  If you need to 'go to disk' in real-time, you're looking at needing
>  at least 3-4 gigabyte/sec of bandwith to disk.  No commodity drives 
>  provide that kind of capacity, so you're looking at multiple drives 
>  'in parallel' -- the logical equivalent of a 'striped' RAID array.  
>  Probably 12-16 spindles paralleled.  Best handled with _hardware_ 
>  raid, directly in the disk controller, but I don't know of a commodity 

Yes.

>  controller that supports enough spindles to give that bandwidth.
>  This means one is best off doing it in the application softwre itself,
>  rather than trusting the O/S to get it right.

Yes.

>   You're also looking at a _big_ disk array. Around 200 gigs for ONE 
>  MINUTE of data.  Need 'only' an hour?  That's merely 12 terabytes.

Yes :)

> The O/S is -relatively- unimportant. <wry grin>

OK. As a recent convert to FreeBSD, I was hoping you would tell me 
that the clean architecture and efficient implementation of FreeBSD would solve
all of my problems :)

> You need _good_ network cards, with good drivers -- preferably ones where
> most of the network stack can be off-loaded onto the card itself.

Yes. Something like TOE, batched interrupts, etc.

> You also need good disk controllers, ideally semi-autonomous (like SCSI),
> with fairly large data buffers.

Yes.

OK. Thanks for the comments, that is helpful. I would be very interested
to hear if anyone has had experience implementing a system like
this (or close to it). I'm trying to decide whether I should try this myself
or proceed with the current linux-based system.