Booting order / SATA onboard / IDE card

[D. Hugh Redelmeier]

| From: Alex Beamish <talexb-Re5JQEeQqe8AvxtiuMwx3w at public.gmane.org>

|  The original NFS server is
| running openSolaris and the drives are using ZFS, in case anyone's
| curious.

I'm not really plugged into the OpenSolaris world, but I wonder how
much longer it will be supported.  The few things I've heard from
Oracle don't make me optimistic.

If you are building a new box, perhaps FreeBSD would be a better
platform.  It supports ZFS.  I have no idea if it understands raw
OpenSolaris disks.

| The intended replacement is a P4 3GHz Dell machine which has a single
| 80G SATA drive. I was planning on buying two 500G or 1T SATA drives as
| the data disks (RAID 1, mirrored), and installing an IDE card for a
| small, inexpensive system disk. However, now I'm wondering whether the
| BIOS on this new machine will be flexible enough to be able to boot
| off the IDE disk; I'm new to SATA drive machines. Anyway, that's plan
| A, and my preferred solution.

Dell boxes can sometimes surprise you with things that they are
missing.  Check if there are places to mount all the drives you want.
Check if there are enough SATA ports (probably).  Check if there is
already a PATA port (sometimes they exist for optical drives).  Think
about cooling.  See what booting options your BIOS provides.

If you plan on running the server 24/7, you might think about power
consumption and heat too.  The fewer spinning disks, the better.  The
fewer P4 processors, the better (0 is optimal).

The incremental cost of a larger SATA disk may be similar to than the
cost of an IDE (parallel ATA) card.  Getting larger disks rather than
an IDE card might reduce the bother and you should end up with a
bigger NFS partition because the OS would only take a tiny fraction of
the additional space.

(Or you could use the same size disk and forgo a few gigs of NFS space
to allow for the OS installation.  But I'm greedy: you can never have
too much disk space (until it comes time to back it up or fsck it).)

Consider getting two 1.5T drives, using the first (modest) partition
on each for the OS, unmirrored, and using the rest of each drive in
RAID1.  Note: I've not tried this; I'm just assuming that it can work.

Why two OS partitions?

1. symmetry -- the drives will have identical partitioning.

2. I always have at least two OS partitions so I can install a new OS
   without blowing away the old one.  Real disk space is so cheap that
   it isn't much of a waste (10G/$, so an OS partition costs a
   dollar or two).

It is true that there might be contention between OS partition
accesses and the RAID partition accesses.  If the thing is only an NFS
server, I'd expect most OS partition accesses to be satisfied from the
filesystem cache so contention ought to be minimal.
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