Re: Slow network performance
From: Stefaan A Eeckels (tengo_at_DELETEMEecc.lu)
Date: 02/03/05
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Date: Thu, 3 Feb 2005 10:19:36 +0100
On 1 Feb 2005 17:13:25 -0800
fong.vang@gmail.com wrote:
> Has anyone experienced any network performance problem with Solaris 8?
No.
> Using scp to transfer large files from a Linux system to a Solaris 8
> system, I'm getting very dismal performance. From Linux to Linux (1
> GHz machines), scp is able to transfer a 97 MB file in 8 seconds.
> This same file takes 51 seconds (from same source Linux system to a
> Solaris
> 8 4-way U450). A file transferred from Solaris to Solaris also takes
> about 51 seconds.
You're probably affected by the fact you're writing the file
to disk. Try the same test using /dev/null or /tmp as destination.
Are you running the destination FS with logging enabled?
To check if you've properly configured UFS write throttling, check the
following entries in /etc/system:
set ufs_ufs_LW = 8388608
set ufs_ufs_HW = 16777216
or you could have disabled write throttling:
set ufs:ufs_WRITES = 0
Also don't forget that Solaris doesn't run with disk write caching
enabled (contrary to many Linux installations), so that pretty
quickly you're up to the limits of the disk and FS instead of the
bare wire speed.
Here's a transfer from a U1/167MHz/S8 to a Blade2000/2x900MHz/S9,
from /tmp to /tmp through a 100Mb/s network, using ftp:
150 Opening BINARY mode data connection for eWA-1_000.zip.
226 Transfer complete.
local: eWA-1_000.zip remote: eWA-1_000.zip
26206654 bytes sent in 2.3 seconds (11260.77 Kbytes/s)
That's close to wire speed (12.5MB/s). Introducing disks in
the equation (from /tmp to /var/tmp):
ftp> cd /var/tmp
250 CWD command successful.
ftp> put eWA-1_000.zip
200 PORT command successful.
150 Opening BINARY mode data connection for eWA-1_000.zip.
226 Transfer complete.
local: eWA-1_000.zip remote: eWA-1_000.zip
26206654 bytes sent in 2.4 seconds (10816.77 Kbytes/s)
The B2000 has a fast FC-AL disk subsystem, which helps, a lot
of RAM, and a logging FS, so it's not overly affected.
Now the opposite direction:
ftp> cd /tmp
250 CWD command successful.
ftp> lcd /var/tmp
Local directory now /var/tmp
ftp> get eWA-1_000.zip
200 PORT command successful.
150 Opening BINARY mode data connection for eWA-1_000.zip (26206654
bytes). 226 Transfer complete.
local: eWA-1_000.zip remote: eWA-1_000.zip
26206654 bytes received in 2.9 seconds (8728.13 Kbytes/s)
The slower disks in the U1 are having an influence on the transfer
speed. It would be worse if logging were switched off.
> Both Linux and Solaris machines have network forced to 100 Mbps
> full-duplex.
I ran the same tests between an Athlon 2000+ (1.6GHz) running Debian
stable and the Blade2000, and the results are in the same ballpark
(11Mb/s from the Athlon to /tmp on the Blade, 8.7MB/s to /tmp on
the Athlon, with has a pretty slow IDE disk).
Using scp, I get the following result from the U1 to the Blade2000:
# time scp eWA-1_000.zip sae@monster:/tmp
sae@monster's password:
eWA-1_000.zip 100% |********************************| 25592 KB
00:14 0.04u 0.58s 0:19.37 3.2%
or only 1828kB/s. scp'ing the same file from the Blade2000 to a
1.6GHz AMD running Debian 3.0 takes 2 seconds, and to an AMD
K6/2 450MHz takes 9 seconds, showing that scp isn't a good test
for wire speed.
> What's strange is that this same setup in 20 different service domain
> (networks) exhibit the same performance problem.
> Any idea? What's wrong with Solaris?
Nothing. Just tune it properly.
-- Stefaan -- As complexity rises, precise statements lose meaning, and meaningful statements lose precision. -- Lotfi Zadeh
- Next message: Thomas Maier-Komor: "Re: Maximum number of threads in a process"
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