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Re: disk partition schemes

On Saturday 23 June 2001 21:13, Nick Jennings wrote:
> > However if you have a single large partition then when you are
> > writing data the FS drivers can optimise things.
>  I always thought that this was a performance hit, I know I've read it
> in places before, but I can't seem to find them as I look right now.

If you are using an older kernel (say 2.0 series) on an SMP machine then 
this could be true.  Older kernels didn't manage SMP very effectively and 
often locked other CPUs out of resources.  Having two separate file 
systems might in some situations allow access to cached data where 
otherwise there would be spinlocks to deal with.

I think that 2.4.x has solved most of these issus (and 2.2.x was much 
better than 2.0.x).

> > Swap is often the most used partition.  Root is probably the least. 
> > /tmp and /home are both candidates for the most used partition. 
> > Having things separate like this means that in many common usage
> > situations you'll have the heads seeking across the entire disk all
> > the time.  Having a single partition could increase performance...
>  Good point, I've put / at the beginning just out of habit, put I think

Same here.  But 1-2 G at the start being reserved for a low utilization 
partition such as root doesn't matter much on a modern 40G+ drive IMHO.

>  that, especially on a server, /var is much more used than home is. and
>  /usr is where every application is executed from, that's gotta count
> for something. I would venture to say that, on a server thats not
> offering lots of shell accounts, /home is the least used.

If the server is an IMAP server then home can still be most used.  But 
really trying to make generalisations about what a "server" does isn't a 
good idea.  There's too many types of servers.

> > If sticking another disk in is so easy then why not just install lots
> > of disks in a RAID array from the start?  That'll get the best
> > performance...
>  Well because a hardware RAID is more expensive than a scsi or ide
> drive. Also because I'm thinking of one disk, with the possible
> expansion onto another one, or two. not starting out with several.

Software RAID is cheap and easy...

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