KVM Switch

[Robert G. Brown]

On Fri, 11 May 2001, Raghubhushan Pasupathy wrote:

> Folks,
>
> I am looking to buy a KVM switch for an 8-node(16 processor) Beowulf
> Cluster. Can anyone give me some directions on this since I am completely
> lost. What specs, brand etc. do you suggest?

Why?  KVM's tend to be very expensive (I know, I have a Raritan which is
an excellent choice and even keyboard-switchable BUT which costs a whole
lot -- good KVM's can cost $100 per port or even more).  I also have a
really cheapo four position mechanical KVM switch that works for
keyboard and video but cannot switch PS2 mice.  It degrades video
quality a bit but is fine for my simple home beowulf, where I have two
or three systems that do a bit of server stuff and hence need a console.

Nowadays a cluster node can run anywhere from totally headless (Scyld, I
believe, is happy enough with no head at all), headless but a serial
port console (a VERY cheap option that is probably adequate for
debugging a dying boot and which can be switched with a cheap serial
switch or managed via a still not very expensive serial port server),
headless but with a cheap video card that one plugs into a monitor one
time (to set the bios and monitor the original install) and then never
again, headed but no X (X plus a GUI is quite expensive in memory and
moderately expensive in wasted CPU), and headed running X.  I now have a
$3000 KVM switch that is more useful for switching between servers
(where one really does sometimes need access to a console) than between
beowulf nodes, which one generally accesses over the net anyway.

I personally generally go with cheap S3 cards (or any sort of onboard
video if the motherboard happens to have it) and no X just to make it a
bit faster to set up the systems and debug them if/when they break.  The
one hassle of running a system with no video card at all is that one
often has to put one in long enough to set up the bios, in particular to
tell the bios to run without a video card without complaining (which
most BIOS's do these days if you ask nicely).  Is the time saved worth
the $30 the card costs per system?  Don't know, but it's close...

   rgb

>
> Raghu
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-- 
Robert G. Brown	                       http://www.phy.duke.edu/~rgb/
Duke University Dept. of Physics, Box 90305
Durham, N.C. 27708-0305
Phone: 1-919-660-2567  Fax: 919-660-2525     email:rgb at phy.duke.edu