[gentoo-amd64] Re: 2nd HDD for var, tmp, usr/portage, swap

[Duncan]

Bernhard Auzinger <e0026053@×××××××××××××××××.at> posted
200707201641.30655.e0026053@×××××××××××××××××.at, excerpted below, on 
Fri, 20 Jul 2007 16:41:30 +0200:

> as I have four hdd's in my computer, I was wondering if it does make
> sense to source out some partitions/directories to a second hdd.
>
> At the moment I have separate partitions for /var, /tmp and /usr/portage
> (I feel portage is a lot faster since I've done this) on the same hdd.
>
> My question is if it makes sence to move these partitions to another
> harddisk?

With four hard drives, particularly if they are near the same size (not 
an old 8 gig on the one end, and a new half terabyte on the other, with 
two in the middle), your best performance is likely to be in RAID.  Here, 
I have four drives in RAID, using the kernel's own md RAID drivers, with 
RAID-1 for /boot, RAID-6 for my main system, and RAID-0 for stuff like 
/usr/portage, /usr/src, my ccache dir, and /tmp (altho with 8 gig memory, 
I actually have /tmp on a memory based tmpfs).  Swap is also setup as 
effectively RAID-0.

Note that RAID using both master and slave on IDE/PATA isn't all that 
efficient, however.  Here, my hard drives are all SATA, tho I'm still 
using PATA CD/DVD drives (but only one on each channel master, not master 
and slave).  Of course, SCSI is its own discussion.

If your drives are different size but all say 80 gig or better, you could 
still do a RAID-0 for speed and put /tmp, swap and the like on that (you 
don't want to put anything important on RAID-0, since if one drives dies, 
you lose everything on the RAID-0, but it's fast, so is good for temp 
stuff like swap and /tmp, and stuff you can download off the net again 
easily if necessary, like the gentoo/portage tree), especially if the 
drives aren't installed as IDE/PATA both master and slave.  If one or 
more of the drives are older and below about 80 gig, chances are it's 
slow enough it'd be bottlenecking the others anyway, so don't bother.

Alternatively, you want to make sure as much as possible, that stuff 
accessed at the same time is on different disks.  Generally, that's the 
same stuff as the candidates for RAID-0 above, swap, /tmp (and /var/tmp), 
ccache, and the gentoo/portage tree, particularly if you tend to do 
emerges in the background while continuing to work on other stuff.  The 
caveat for swap is that the newer and therefore larger drives tend to be 
faster, and it's them that generally have the main system on them already 
(unless you have your largest drive as a dedicated media drive as some 
people do).  It's often most convenient to try swap on the old/slow 
drive, but of course, that can be counter-productive.  Still, it 
depends.  It may still be faster on it, than having the new/fast drive 
trying to handle both system and swap at the same time, even if the swap 
drive /is/ your old/slow one.

-- 
Duncan - List replies preferred.   No HTML msgs.
"Every nonfree program has a lord, a master --
and if you use the program, he is your master."  Richard Stallman

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