[ale] VM guest partitioning practices

[Ted W.]

On 12/09/2014 02:40 PM, Todor Fassl wrote:
> I think creating a seperate partition for /var (at least) is counter
> productive. If /var fills up, your machine is going to go down because a
> lot of services will hang if they can't write to the syslog.  Similar
> logic applies to /usr. I can see having a seperate partion for /home but
> that is about it.

I have to disagree with this. There are built in mechanisms, at least in 
RHEL, which can cleanly drop the system to single user mode should 
/var/log fill up. In a situation where it fills up on a separate 
partition, you can have the system drop to runlevel 1 at which time 
nagios, or similar, would tell you the system has gone down and you can 
investigate at the console. If you don't have /var on a separate 
partition, the system /may/ still drop to runlevel 1 but the system 
would be equally as likely to crash, in a much less graceful manner, for 
reasons stated above. While the end result is the same (system down, 
services unavailable), the later seems much less desirable to me.

In a VM environment where disks can be expanded nearly infinitely (or as 
far as the physical storage system will allow), I see little argument 
against NOT separating at least /home, /var (or /var/log at least), /srv 
and / on to their own logical volumes and /boot on to it's own 
partition. At worst you wasted a few lines in a ks.cfg partition recipe. 
At best, your saved your filesystem from a hard reset when the system 
locked up.

I guess my point in all that is I see more harm then good in not 
separating certain partitions, particularly /var. In our production 
systems we split /home, /srv, /var/log and / in to their own logical 
volumes and /boot lives on a small sliver at sda1. This has worked well 
for us on both physical and virtual servers alike.

-- 
Ted W. <ted at xy0.org>