Subject: Re: small home file/backup server
To: Steve Bellovin <>
From: Wojciech Puchar <>
List: netbsd-users
Date: 08/22/2002 13:06:54
> I'm going to be building a small (i.e., cheap) home file server.  The
> primary use is for backup copies of a few Windows file systems, via a
> switched 100BaseT network.  I have a 60G, 7200 rpm, ATA/133 drive lying
> around; I'm contemplating buying another and setting up a RAID
> environment.  But I've never built such a system before.

why you need "RAID environment"?
is that need based on some calculations etc or just cause it is popular?

as stated in raid(4) RAID isn't the replacement of good backup practice.
and it is absolutely true from my practice.

if you like simply to have all space in one filesystem use ccd(4).
works excellent.

> So -- should I use two drives, each on one of the two IDE channels on
> the motherboard?  The CD drive would be very lightly used, except for

you must have new CD drive capable of DMA modes. or disk on same channel
will be downgraded.

> NetBSD installations and upgrades.  Buy an outboard IDE controller?

no need. but if you can live without CD-ROM better don't put it here.
master/slave interaction on IDE is what i always want to avoid....

put floppy drive, boot from floppy, install system through network.

> project.)  Would I be better off with a small system disk, plus two
> RAID drives for data?

no. good idea is to make small RAID1 filesystem for / and swap(for eg. 1GB
on each drive) and ccd device from the rest (2*59GB).
ccd device option for just concatenate drives is good - as FFS spreads
different data in different cylgroup by itself. and you can buy different
sized drive (like 80GB).

> Which RAID should I use?  Is RAID1 sufficient, or should I use 4 or 5?
> (The goal is reliability, not speed.)

if you really need reliability buy backup device like DDS3 or DDS4 drive.

you may do RAID1 but it does protect you ONLY from disk failure.
not from any other machine malfunction that may cause for eg. writing
nonsense to filesystem metadata.
it doesn't protect you from accidental rm etc...

RAID5 requires at least 3 disks, and it's really slow on writes.
and will be until NetBSD will have MAXBSIZE higher than 64kB and will be
possible to make RAID5 filesystem with stripes like 256kB or more (modern
drives can read 300-500kB in time needed to do average seek).

RAID5 gives the most space out of drives, but is slowest. with todays
cheap and huge IDE drives it doesn't make much sense.

> How much CPU do I need?  Would a 233 Mhz Pentium or a 350 Mhz P II

my Pentium 133 is able to keep up with 100Mbps NIC as nfs server giving
8-9MB/s , but it's about 100% CPU. so P233MMX is more than enough if this
will be mostly fileserver

important thing is chipset used, with VIA based PMMX you may experience
low disk transfers in best case (or crashes in worst). if it's intel TX or
VX - use it.