Re: Software vs. Hardware RAID 1

On 11 Jul 2006 02:26:01 GMT, x0054 staggered into the Black Sun and said:
Dances With Crows <danSPANceswitTRAPhcrows@xxxxxxxxx> wrote:
x0054 wrote:
What I am wondering is how software RAID1 [compares] with HW RAID1
and if there are any significant advantages or drawbacks to either.
SoftRAID-1 will probably be *faster* than doing RAID in hardware.
The main problem is that softRAID is a bit less transparent than
hardware RAID. Just read the RAID HOWTO and you'll be fine.
Thanks, that sounds great. Yeah, actually I probably would disconnect
the CD-ROM after install all together. Really the only reason for it
is to load Debian.

It'd probably be a good idea to keep the CD-R* connected, because it's a
pain to reconnect it if you need it later. And you probably will at
some point.

I looked though SW RAID setup, and it looks very straightforward.
When setting up [the] bootloader, would I tell it to boot from hda or
hdc, or can I specify md0 (the SW raid disk)?

GRUB and LILO don't grok RAID. You'd install the bootloader to /dev/hda
(or (hd0) ) and pass the "root=/dev/md0" option to the kernel. Like so:

machine:~# grub
grub> root(hdX,Y) # replace with numbers of /boot partition
grub> setup(hd0) # install bootloader to MBR of first disk
grub> quit # done; write or modify grub.conf to taste

Of course, you'll have to have softRAID-1 built in to the kernel or
available in the initrd for that to work. The default Debian kernel has
those things available, just remember to build that stuff in when you
compile a custom kernel.

If I specify the actual disk I would have to change it respective to
the disk. Right? So on hda the bootloader would be set to boot from
hda and on hdc it would be set to hdc?

What? Install the bootloader on /dev/hda, use dd to copy the first 63
sectors to /dev/hdc . If /dev/hda dies and you have to reboot, you're
going to have to switch some cables around, but you'd have to do that
*anyway* because you'd be replacing the dead disk. HTH,

--
Matt G|There is no Darkness in Eternity/But only Light too dim for us to see
Brainbench MVP for Linux Admin / mail: TRAP + SPAN don't belong
http://www.brainbench.com / "He is a rhythmic movement of the
-----------------------------/ penguins, is Tux." --MegaHAL
.

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