[ILUG] New system - final preparations before deployment.

[Conor Wynne]

> On Tue, 7 Sep 2004, Conor Wynne wrote:
>
>> I created 4 RAID volumes as follows:
>>
>> 1. /dev/md0 (100MB for /boot ext3 - RAID1)
>> 2. /dev/md1 (18GB LVM2 - RAID1)
>> 3. /dev/md2 (18GB LVM2 - RAID0)
>>
>> I decided on raid0 for SWAP,
>
> Eek. Swap is *not* discardable. It could contain data (eg that email
> you started writing on another dekstop) which an application hasnt
> written out.

Yes, I did actually think of that. But since the system has 1GB RAM, and
-so far- swap does not even come into the equation (I will not -yet- be
running any databases on it)

I had a case with an "unnamed company" with 46 days of uptime with no
probs. Oracle 10G db and other development apps etc. On day 47, everything
slowed to a crawl and they were getting zombies (oracle processes
unsurprisingly). The problem was indeed due to lack of swap space on a
512MB system. As soon as I added some swap the system immediately started
using it and the system became usable again.

> Further, while the data on swap might not be that terribly missed, a
> disk failure will likely kill your machine now, which makes it
> difficult for machine to write out non-discardable data...

OK, what I can do is add a spare swap "file" instead of a real type 82
jobby. I do not think I will go near the swappiness proc settings on this
box.

>
>> /tmp & finally /squid-cache, as all the data therein is
>> discardable. So RAID0 gives the best disk usage and is fast.
>
> tmpfs is even faster for /tmp (and is backed by swap).

Hmm, must look into that. But first I will monitor it over a month or so
and see if it actually uses swap space. I installed a minimal distro with
only httpd, cyrus-imap, sendmail, spamassas-milter, clamav-milter and
development tools, no X or any client apps whatsoever, samba is installed
but disabled and unconfigured, apt-get, cronjobs for monitoring raid and
logs, mailman and a few others.

>> The RAID level 1 volumes, LVM based, contain /, /var & /home. So I
>> am now happy with this,
>
> / on LVM? Fair enough, but if ever anything goes wrong you'll need a
> rescue disk with lvm2 tools. / directly on RAID1 is a much easier
> rescue position - you dont even need RAID support to access your
> data.

Aha, but thats where the wonderfull installer cd from fedora2 comes in.
All I have to do is boot from either a rescue cd, or type "linux rescue"
on CD1 on fedora core2, and then chroot blah blah and I'm in. Sweet :)

>> Can I do this with a single IPaddress on my router?
>
> yes.
>
>> But the issue as I see it is how to configure apache so that when
>> someone goes www.foo.com or www.bar.org that it goes to a different
>> webpage. I believe this is possible with the virtual hosts options
>> in httpd.conf? Is that correct?
>
> yes.
>
>> What about MX records? Will they be fine if I setup multiple domains? I
>
> yes.
>
>> Anyone see an issue with this config?
>
> other than above, no.

Great stuff, thanks for that Paul.

>
>> p.s.: I think I may end up putting this server into the garden
>> shed, depends on what the missus says.
>
> that sounds like a good idea. btw, where do you live?

Lucan, Capitale mondiale, not too far from Niall actually.
The wesht is the besht :)

> --
> Paul Jakma	paul at clubi.ie	paul at jakma.org	Key ID: 64A2FF6A

p.s.: Thanks to Michele & Conall aswell for the helpfull advice.
Niall says I have to announce a LEWD soon so I will buy you lads a pint in
payment.

Conor Wynne
Dublin
Irlande.