[K12OSN] Adding another server as backup.
Martin Woolley
sysadmin at handsworth.bham.sch.uk
Wed May 11 13:32:26 UTC 2005
On Wednesday 11 May 2005 09:02, Sudev Barar wrote:
> How is the home directory served? By a different backbone on all
> servers?
Some via NIS/NFS some via Samba depending on the how long the student has been
with us. For NIS, I've scattered the home directories evenly amongst the
servers and each server has the /home directory of all the others mounted via
NFS. Each server has a directory under /home which corresponds to each of
the servers, thus we have /home/LISA, /home/BART, /home/MARGE, etc.
Here is a 'df' for lisa
/dev/hda3 3526204 214412 3132668 7% /usr/local
192.168.0.2:/home 59717280 10127936 46555872 18% /home/HOMER
192.168.0.3:/home 59717280 8552608 48131200 16% /home/MARGE
192.168.0.4:/home 59717280 8435520 48248288 15% /home/BART
192.168.0.9:/home 100932544 8421824 87383584 9% /home/MRBURNS
192.168.0.10:/home 59661024 4569632 52060736 9% /home/MAGGIE
See how all of the /home directories for each of the other servers are mounted
on 'lisa'. A similar configuration is in place on the other servers. Now on
'lisa' the /home/LISA directory contains a bunch on sym links to the home
dirs that reside on lisa and similarly on the other servers.
# ls -ld /home/LISA
lrwxrwxrwx 1 root root 13 Nov 2 2004 adnam04 -> /home/adnam04
lrwxrwxrwx 1 root root 13 Dec 8 13:37 alhog03 -> /home/alhog03
lrwxrwxrwx 1 root root 13 Nov 2 2004 alixm04 -> /home/alixm04
lrwxrwxrwx 1 root root 13 Nov 2 2004 almua04 -> /home/almua04
etc
The final bit of the jigsaw is the password file. The YP server runs on lisa
so each user is authenticated by that box.
# tail /etc/passwd
sanda04:x:720:100:Sandhu Aaron:/home/MAGGIE/sanda04:/bin/bash
shara04:x:721:100:Sharif Aadam:/home/MRBURNS/shara04:/bin/bash
sharp04:x:722:100:Sharma Pavan:/home/LISA/sharp04:/bin/bash
verma04:x:723:100:Verma Akshay:/home/MARGE/verma04:/bin/bash
shahi99:x:724:100:Shahan Imran:/home/LISA/shahi99:/bin/bash
Notice that the home dirs are scattered across the servers. Thus no matter
which host provides the user with a login, their home dir is still
accessible.
> Very interesting......Did I hear a collective gasp of all the load-
> balancing scripting guys?
I doubt it; our solution is not the most elegant and there are no doubt huge
bottlenecks in the works. Access times are acceptable but not brilliant.
Most of the students use the IT suites for web surfing (and playing games on
the internet). I don't really care how slow their internet access is. Word
processing (the other big load) is usable once the document is loaded. What
I'd really like to see is a multi-processor setup and a huge raid farm for
the home dirs; something like the Beowulf cluster might do the job. We have
aquired an IBM RS/6000 SP/2 which will do exactly what I want. Now if only I
can find the time to set the beasty up.
--
Regards
Martin Woolley
ICT Support
Handsworth Grammar School
Isis Astarte Diana Hecate Demeter Kali Inanna
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