file server question
davecb at canada.sun.com
Mon May 14 13:22:52 GMT 2001
Lajber Zoltan wrote:
> We have been invited a tender by the Edu. ministry of Hungary. We
> are thinking about a "big" central file server for about 1500 named
> clients. We expecting about 400-500 simultaneous light office clients.
> The network is mostly fast ethernet, with gigabit backbone constructed
> with cisco elements (7206, 2948G-L3, 2924M-XL...).
Ok, here's the assumptions and computation:
500 office users * 1 IO/second * 8 KB/IO ~= 4000 KB/S
2 * Ultra 200 CPU (the newest I have data for) = 5300 KB/S
8 * 7200 rpm disks (ditto) = 4480 KB/S
1 * fast Ethernet (tritto) = 6500 KB/S
min(5300, 4480, 6500) = 4480 KB/S
Therefor: if you configure less than 2 slow CPUs,
1 100 Mbit/S ethernet and 8 fast disks, you
For each **active** user, allocate 1 MB of memory,
as it will be used for disk cache for the disks
you're serving (the application usage is much
smaller than that, more like ~760 KB)
For each inactive user, allocate 1 MB of swap, so
you won't refuse connections.
You'll want to figure in
- room of estimation error (!)
- headroom for expansion over time
The things to watch out for are
- not having a box which is expandable to
the memory and cpus required for at least
twice the initia lestimate
- buying too few disk **heads**, and not
RAIDing them together. Throughput, not
capacity, is the problem of the 1990s.
- starting with a single cpu: dual cpus
are A Real Good Thing for reducing
latency and increasing response under
> Fortunately we are unix (sun+solaris, netfin+linux) shop, but have no
> experienc to size such machine.
> Our expectation is about an Ultra Enterprise 450, or a Fire 3800.
> Becouse the 5 VLANs, I prefering a quad fast ethernet NIC for load
> balancing, but a single gigabit interface possible, if it's better.
> Thanks for your effort.
> LAJBER Zoltan, Szent Istvan Egyetem, Godollo, IKKP-Informatika Osztaly
> http://mlf.linux.rulez.org http://pecalista.rulez.org
David Collier-Brown, | Always do right. This will gratify
Performance & Engineering Team | some people and astonish the rest.
Americas Customer Engineering | -- Mark Twain
(905) 415-2849 | davecb at canada.sun.com
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