Very Computer

by **rgi..** » Fri, 30 Sep 1994 20:18:07

We have a Linux box which is responsible for all things Internet. It's main
job is to act as a news server, receiving a continous live feed from our
eviceprovider.

We have noticed that when news is coming in the whole TCP/IP sub-system slows
down rediculesly. Using 'top' you can see that the machine has some 9 meg. of
free memory (used as buffers) and has 80% idle time, but any net related
commandssuch as 'route' or 'netstat' will print a bit of their tables and
then freeze for 20 or so seconds and then continue. Remote telnet is the
same. Although the connectforms instantly, it takes a further 20 or so
seconds for the login prompt to appear(same for ftp). Our news feed is via a
64K link and so can't possibly be strainingthe network very much at all.

Any ideas?

I have the latest kenel (1.1.45), would the 'load balancing (experimental)'
helpat all? (it's switched off at the moment)

Thanks for any help/comments.

oh yes, the spec.

33Mhz 486. 16 Meg RAM, 17 Meg. swap partition
500 Meg. IDE drive mounted as root (ext2)
1 Gig. SCSI on Adaptec 1542 (ext2)- 512 meg. mounted as /var/spool/news, the
rest not used.Intel Ether express network
card.

by **Alan C** » Tue, 04 Oct 1994 23:14:14

>We have noticed that when news is coming in the whole TCP/IP sub-system slows
>down rediculesly. Using 'top' you can see that the machine has some 9 meg. of
>free memory (used as buffers) and has 80% idle time, but any net related
>commandssuch as 'route' or 'netstat' will print a bit of their tables and
>then freeze for 20 or so seconds and then continue. Remote telnet is the
>same. Although the connectforms instantly, it takes a further 20 or so
>seconds for the login prompt to appear(same for ftp). Our news feed is via a
>64K link and so can't possibly be strainingthe network very much at all.

>Any ideas?

This sounds quite normal. Your name service is slowing down a lot with the
huge backlog of network traffic down your 64K pipe. If you can make sure
your provider supports IP_TOS properly (ie priority ordered packet queues)
and get the newsfeed to run at the lowest priority it will help, as will
having your nameserver cache other sites.

Alan
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by **Bart Kin** » Sun, 09 Oct 1994 15:36:15

>Newsgroups: comp.os.linux.help
>Path: otago.ac.nz!canterbury.ac.nz!waikato!wupost!howland.reston.ans.net!news.sprintlink.net!demon!betanews.demon.net!news

>Subject: TCP/IP sub-system going very slow?

>Lines: 27

>Nntp-Posting-Host: rgiles.fisonssurf.co.uk
>Organization: Demon Internet
>X-Newsreader: LA Times for OS/2 [version: 3.2 UNREGISTERED 20 days remaining]
>Date: Thu, 29 Sep 1994 11:18:07 GMT
>We have a Linux box which is responsible for all things Internet. It's main
>job is to act as a news server, receiving a continous live feed from our
>eviceprovider.
>We have noticed that when news is coming in the whole TCP/IP sub-system slows
>down rediculesly. Using 'top' you can see that the machine has some 9 meg. of
>free memory (used as buffers) and has 80% idle time, but any net related
>commandssuch as 'route' or 'netstat' will print a bit of their tables and
>then freeze for 20 or so seconds and then continue.

This is caused by the fact that it attemps to do a DNS lookup for every IP
connection. Use netstat -n instead. (Where is your Name Server..?)

Quote:>Remote telnet is the
>same. Although the connectforms instantly, it takes a further 20 or so
>seconds for the login prompt to appear(same for ftp). Our news feed is via a
>64K link and so can't possibly be strainingthe network very much at all.

There could be some other problems involved as well. Have a look at the Name
server setup anyway.

Bart.

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Bart Kindt (ZL4FOX) System Operator, Efficient Software NZ LTD, Dunedin, New Zealand
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