Allo,

All the tools named previously are great, but to find the problem it
will greatly help if you can answer these questions first before
doing any technical investigations in talking with the people that
are actually using the network:

- How many users do you have running simultaneous vpn?
- How many users do you have on your network (lan)?
- Have you other users running other non-vpn processes which are using
   the adsl connection like ftp, scp, sftp, torrent, web server, etc...
   For example, if someone is doing an upload of a 50MB file everyday
   in scp (or even through vpn), he will almost block all other users to 
   a crawl if no priority (QoS) or a limit (scp -l) is used. To upload
   a 50MB file takes about 10 minutes (at 800Kb/s) and during this
   10 minutes, it's hell for everybody!
- Is there a lot of users getting live streams and passing through
   the vpn to have them (ouch!): youtube, online music, voip, etc...
- What is the provider and at what time are you experiencing your
   slowdowns. Some providers throttle during businness day if they don't 
   know what is transfered, unless you have a fix business ip.
   Others don't. You will have to find out. Try your tests at night
   to see if the slowdowns are also occuring.
- What are the specifications of the router (GHz, MHz, ram) and
   the load (and/or uptime of the machine). A "vmstat 1 10" will
   give us a lot of information on the router CPU and RAM state.
   Also, a simple "netstat -tan" will show you all actual TCP
   connections and "netstat -uan" will shou you all UDP connections.
- When you say "remote desktop" are you talking about "windows
   remote desktop" protocol or the vnc protocol? In either case,
   what is the resolution of the screen, the bit depth and also,
   are the screens mainly static (change every 5 to 10 seconds)
   or mainly dynamic (change every second)? Using 8 bit colors
   instead of 16 or 32 makes a very big difference.
- Since how long do you have this problem? And did it happen
   suddenly (provider gift) or progressively (more users are added)?
- Have you done a profiling to know when the slowdowns actually occur?
   1 hour a day? 8 hours a day? All the time? When John is "working"?
   No problem on week-ends? 

Please, keep us informed ... Food for the mind.

On Mon, Aug 23, 2010 at 09:58:52AM -0400, Patricia Campbell wrote:
>From: Patricia Campbell <[email protected]>
>Date: Mon, 23 Aug 2010 09:58:52 -0400
>To: Montreal Linux Users Group <[email protected]>
>Subject: [MLUG] pinpointing bottlenecks ??
>
>Hello All,
>
>I haven't done traffic monitoring in a while so I'm asking you all for
>any new tips & tricks!!!
>
>The sit:
>ADSL connection 3.0Mbps
>ipcop firewall + openvpn  (admittedly on an older computer)
>lan @ 100Mbps
>remote desktop on computers
>
>We get very slow access and I'm trying to determine if there is
>anything I can tweak on my side.
>
>Does anyone have any well loved tools (that I haven't heard of yet ???)
>
>Thanks
>
>-- 
>___..___........__.......__
>...|....|__/....|...|......|...|__|
>...|....|.....\...|...|__..|...|....|
>
>"You must be the change you wish to see in the world." Mohandas K Gandhi
>_______________________________________________
>mlug mailing list
>[email protected]
>https://listes.koumbit.net/cgi-bin/mailman/listinfo/mlug-listserv.mlug.ca
_______________________________________________
mlug mailing list
[email protected]
https://listes.koumbit.net/cgi-bin/mailman/listinfo/mlug-listserv.mlug.ca

Reply via email to