Subject: Re: Separate /usr, etc...
To: NetBSD-current Discussion List <current-users@NetBSD.ORG>
From: Greg A. Woods <>
List: current-users
Date: 12/16/2002 02:29:05
[ On Sunday, December 15, 2002 at 22:38:48 (-0800), Greywolf wrote: ]
> Subject: Re: Separate /usr, etc...
> I'm actually kinda there myself.  If I have the opportunity, though,
> I can accurately partition for everything the system will use, and won't
> have to repartition again.

So, what do you do with an 80GB drive on a general purpose server?  What
if it were a 320GB drive?  :-)

Disk is now _much_ cheaper per GB with new retail drives than it was per
MB for used/surplus drives back when I bought my first 140MB ST-506
drive.  Since I'm not a multi-media nut, and since I have a high-speed
Internet connection for downloads of new software and such, I just don't
know what to with all that much space.  Even my 20GB /home is only just
now half full after a couple of years, and I'm keeping all kinds of junk
there that I don't really need, like lots of downloaded PDFs, etc.

> # I suppose ideally, on modern machines especially, all individual disks
> # should be mirrored, especially for root and swap partitions, and all
> # other file systems should be at least mirrored, if not RAID-5.
> I don't understand mirroring swap.  I guess I'm stupid.  Please, enlighten
> me.

If you're going to bother mirroring anything (and/or using RAID-5) then
presumably you're concerned about high availability, not just reliabilty.

If you didn't care about high availability then your ordinary backups to
removable media, the kind you use for true disaster recovery, would
suffice, right?  Your need for high availability is what drives you to
paying for it with some of your performance and system resources.  If
you didn't need high availability then you could run a cheaper, and
probably faster, system.

The idea is to mirror every partition on a pair of disks so that if one
spindle kaks out then your system can continue running without even a
reboot (assuming your disk controller and/or driver doesn't lock up
because of the pooched drive) until a replacement shows up or until you
can schedule downtime for a repair that won't disturb your users quite
so much.

If you don't mirror your swap partition too then when one of the disks
dies your machine probably just panics.  Maybe it'll reboot, but maybe a
lot of damage to your running services and their files will already have
been done because of the panic (these kind always happen at the worst
time when everything's the most busy and there are many unwritten

								Greg A. Woods

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