Re: [Ltsp-discuss] server recommendations

[Joe Baker]

nigel barker wrote: Hi folks I was under the impression that RAM is everything in the server, so I built one with a 2G celeron and 2G of RAM. However the CPU regularly runs at 100% with only 10-15 clients, and there are unacceptable delays for those clients. The RAM usage has never even reached 1G and swap is of course untouched. All clients use Icewm, and the main things they run are open office, firefox, konqueror file manager and the occasional gimp. What do I really need to support 20-25 clients? I don't think I can afford dual CPU. Is it better to run two modest servers with load balancing(I see there's a howto on that), or should I just go for the fastest processor I can afford? Does a 64bit CPU make any difference? I'd be really interested to hear your actual experiences instead of reading all this apparently false theory on web pages. Thanks a lot Hi Nigel, One CPU load hog is IDE Disk I/O.  I've been told that SCSI is better or to get a RAID controller like the ones made by 3ware. One other thing that might improve your system is CPU  cache memory. If you had a Pentium in there with 1MB of Cache & Hyperthreading I'd bet you'd see some drop in the CPU load.  (Note there are presently security issues with Intel Hyperthreading CPUs) 64 bit CPU would make all the difference in the world!  Faster RAM access by far, dual core cpus.  But come on, a Celeron in your sever? Here's another expansion technique.  Use another box to run your Open Office application.  Have it run nothing else but Open Office for all the users. Make sure you have 1MB or 2MB of cache ram on the processor.  This isn't really a load-balancing technique, it is isolating specific computers to specific tasks. Also consider your present motherboard.  Does it use DDR memory or PC100? DDR would be significantly faster. Presently I get good mileage from our Pentium 2.4 GHz with just 512k of CPU Cache with about 5 thin clients, SAMBA & CUPS server for 35 Windows clients (DDR with parity ram)  It's a Dell 600sc server with IDE drives and no special controller.  Where I spike the load is when I perform heavy disk I/O and use heavy compression to backup workstations using rdiff-backup. We are working on implementing Wine for running Windows applications, I also run VMWare on the box (with Gentoo and WindowsXP, and Windows 98 as guest Operating Systems). Congrats on rolling your systems out as far as you have.  I feel your pain with your unexpected performance hit.  These are hard lessons to learn.  I once tried what you are doing in a classroom experiment with an AMD Duron 1700 with 1 Gigabyte of ram.  Only the workstations were running KDE with full glitz turned on!  My cpu-load skyrocketed to about 20 :) I had PC100 ram, very little cpu-cache ram and all the IDE disk i/o took it's toll on the cpu as well. -Joe Baker  Burlington, Wisconsin  & St. Louis, Missouri