Hi Shane,
I am running SMP with software RAID. It works great...
Installing is a real pain though. You need an additional drive, really. I
am doing software RAID 1 on two systems, one SCSI and one IDE. The SCSI
system is SMP, has a matched pair of SCSI drives, and an 8Gb IDE drive. I
installed RH6.0 onto the IDE, then partitioned the SCSI drives
identically, setting the partition types to 'fd', which is RAID
autodetect. Formatted the md devices, and mounted the whole structure
under /mnt/raid. Then I used tar to copy the file structures from the IDE
drive to the RAID partitions. I have a /boot partition on each SCSI
device, not mirrored and not mounted, but you need them for booting. I
have mine set up so that I can boot off of either (they are on separate
channels which I can switch from the SCSI bios, and they both have LILO
installed). Make a backup of your raidtab, because it sometimes
mysteriously disappears. Edit /mnt/raid/etc/fstab to refer to the RAID
partitions, reboot and pray. Red Hat forgot to include the RAID drivers
in initrd in RH6.0, so I had to make a new one so that the autodetect
would work at boot time, so that the root partition could be mounted.
The mirrored IDE system went a little more smoothly. I used RH6.1, and
initrd includes that RAID drivers. The drives were not quite the same
size, so I installed a minimal system on the extra space on one drive
(tight squeeze), did the same setup, but used rsync to do the copy (much
easier, although I think it was a little slower, but that could have been
the hardware), added a "raid" entry in lilo. Worked like a charm. Then I
used rpm to add all the stuff I hadn't been able to fit on the minimal
installation.
I couldn't tell you about Dell systems. I looked at them, then decided to
build my own SMP system. It was much cheaper. I used a Supermicro D6DBS
mainboard with dual channel Ultra Wide SCSI. They also have an Ultra2
mobo, but it is only single channel. A pair of Seagate Barracudas, and
256Mb of memory. Dual 400 MHz P-IIs. The mobo will handle up to 600MHz
P-IIIs. My only complaint is that the BIOS does stupid things unless you
manually assign IRQs. The first time I brought it up with two ethernet
cards, it put them both on the same IRQ, along with the video... Then when
I assigned one of them manually, it put the other on the same IRQ as the
SCSI controller. I got the most interesting error message:
"eth0: something WICKED happened"
Once I fixed it, I had to boot off the IDE and reconfigure/recopy the RAID
partitions because one was hosed, and I didn't trust the others...
System has been running smoothly since then (September), with the only
downtime due to installing new hardware, and one power outage. One of
these days I must get a UPS. However the RAID devices resynced themselves
without a hitch.
Hope this helps,
Simon
On Tue, 11 Jan 2000, Shane Williams wrote:
> The department I work for is about ready to ditch Solaris in favor of
> Linux (due primarily to the cost and pain of maintaining Sun
> hardware). As the long time Linux evangelist, I'm now primarily
> responsible for deciding on a configuration for the new machine.
> When it comes to Linux, there are two issues that I feel underinformed
> on: RAID and SMP support. While I've had lots of experience with Linux
> over the years, I've never had an opportunity to try out its RAID or
> SMP capabilities. I can remember a time when neither of these
> functionalities was quite ready for prime-time, but my impression is
> that support is now fairly dependable for both of these.
>
> Aside from the generic advantages of these features, how is using RAID
> and/or SMP with Linux going to affect my life? Particularly with
> RAID, does anyone have any experience regarding software vs. hardware
> based RAID? How about internal vs. external hardware RAIDS? I've
> read in places that especially on fast SMP machines that software RAID
> is just as fast as hardware.
>
> Finally, does anyone have any vendor reccommendations? Has anyone
> bought Linux servers from Dell?
>
> Thank you greatly for any and all help.
>
> --
> Public key at www-swiss.ai.mit.edu | Shane Williams
> /~bal/pks-toplev.html | Systems Administrator UT-GSLIS
> =----------------------------------+-------------------------------
> All syllogisms contain three lines | [EMAIL PROTECTED]
> Therefore this is not a syllogism | www.gslis.utexas.edu/~shanew
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