[Beowulf] No guards on 1u server fans - common practice?

stephen mulcahy smulcahy at atlanticlinux.ie
Fri Mar 13 04:50:46 PDT 2009


I have inherited 40 servers which I'm currently building a Hadoop[1] 
cluster out of (I know, not typical beowulf fare but we're using the 
same principles to roll out the systems, manage them and so on).

We've been upgrading the drives in these servers (they are a few years 
old and came with 1 x 80GB drives, we're moving to 2 x 1TB drives since 
we're using Hadoop mainly for it's distributed filesystem properties) 
and I've run into a few problems now with a pretty simple problem.

I guess I'm mailing the beowulf list with a view to adding something 
else to your list of things to look out for when troubleshooting servers 
and to query as to what I've found is general practice.

We ran into some fan problems after powering up some of the systems to 
do initial smoke testing. After a little head-scratching and looking at 
a system running on a workbench - it became obvious what was causing the 
fans to fail. The SATA power cables and in some cases, the SATA data 
cables were sticking into some of the fans blocking them. Hence the error.

The fans don't feature any guards (plastic or metal). I've since 
re-examined all the systems and in most cases, we had inadvertently 
created these cable+fan problems during the installation of the second 
drive. The only way to avoid if that I can see is to stuff the excess 
cable under one of the drives. This is fine, now that I realise it is 
neccesary but it strikes me that unguarded fans in 1u servers with very 
little space for cables is a pretty poor design. I don't think I've seen 
this in other 1u servers I've worked on (but I'll certainly be keeping 
an eye out in future).

Is this really poor design (the server vendor shall go nameless though 
they are a tier-1) or am I expecting too much out of 1u server fans?


[1] http://hadoop.apache.org/core/
Stephen Mulcahy     Atlantic Linux         http://www.atlanticlinux.ie
Registered in Ireland, no. 376591 (144 Ros Caoin, Roscam, Galway)

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