Skip site navigation (1)Skip section navigation (2)
Date:      Tue, 6 Jul 2004 18:53:04 +0000 (UTC)
From:      naddy@mips.inka.de (Christian Weisgerber)
To:        freebsd-hackers@freebsd.org
Subject:   Re: concurrent scp transfers (and a testing methodology ?)
Message-ID:  <cceseg$efq$1@kemoauc.mips.inka.de>
References:  <20040705205100.88989.qmail@web53307.mail.yahoo.com>

next in thread | previous in thread | raw e-mail | index | archive | help
Joe Schmoe <non_secure@yahoo.com> wrote:

> However, I wonder how well this relates to how many
> ssh sessions (scp file transfers, specifically) that a
> FreeBSD server can handle.  Can anyone throw out some
> basic numbers for this ?  Assuming a 1ghz p3 and 2gigs
> of RAM, and assuming that everyone is transferring a
> totally different file.

In LAN environments, scp is conspicuously CPU limited.  A P3/1GHz
will be able to push out a file at about 6MB/s.  Divide by desired
number of files.  Just what transfer rates did you have in mind?

> I would think the major bottleneck would be disk

I don't think so.  If you have many concurrent transfers of different
files spread out wildly over the disk, you might get the disk to
thrash, but it isn't clear that it will still matter at this point.
Check some "random reads" benchmarks for your vintage of disk.

> (like, does SMP help a lot here, or just a little ?)

A lot, as far as SMP goes.

Alternatively, a lowly VIA C3 Nehemiah with its on-core AES engine
should happily beat your usual high-end P4/Athlon/etc at this task.
(I don't know whether FreeBSD integrates the AES engine in userland.
OpenBSD does.)

-- 
Christian "naddy" Weisgerber                          naddy@mips.inka.de



Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?cceseg$efq$1>