(posting on Jeff's behalf)
Oldest story in the book, I think. I believe a flaky power supply is the source of all my server woes, making me BELIEVE I had problems with hard drives and motherboards (and even my linksys wrt-54GS!).
I originally thought the trouble was an 'incompatible' samsung hard drive, so I replaced it with a Maxtor (eww). Then I had trouble with the network card too (that was what happened with your rsync that night, phil, it wedged my network driver - happened again later), so I got a new motherboard. Both problems were always under heavy disk/net load, respectively. So the new mobo and drive made the problems all go away. I did try to get the samsung to work with the new motherboard, to no avail.
So I had thus concluded that both the Samsung drive and the XFX 630i motherboard were not very compatible with Linux. It didn't make sense (nvidia SATA should work fine), but empirically it was proven to be the case. I also found a thread of another guy having trouble with HIS samsung drive in linux, which added to my FUD WRT the samsung.
So because I have so many drives now (I can't return that samsung, so I'm using it in my gaming box), I tried to add a 4th hard drive to my 'now stable' system. The new drive is a seagate 750G, very similar to the original 2 seagate 500's that have been happily running in the system for years. When I did this, I found that one of the older, more reliable drives was starting to freak out!
So, to remove my suspicion that the PSU was bad, I swapped out the (crappy) 420W for a (slightly less crappy) 300W. I suspected the PSU because a) it's not a brand name PSU, b) the molex connectors have always been really loose, which just bugs me, and c) it did sound like the samsung was 'restarting' a lot, which just always seemed like it wasn't getting enough power.
The problems are gone.
Should I do all the work to start over, put the mobo and samsung back in with this other PSU, and see if it all 'just works'? Then I could return the new motherboard (which I'd have to reswap with my gaming rig), and the maxtor drive, and copy a bunch of files around). As it sits, I have tons of extra disk storage (which I can use for TV shows and backup space), and an extra xfx motherboard sitting in a box.
So much work. And I'm sick of screwing around with computer crap! But I'm oh so curious to know if the original setup was just fine...
A Couple side notes
Linux software raid is awesome.
After so many flaky drive screwups, and 'out of sync' raid configs, and reboots (some after crashes), I have not lost a single byte of data. I've had to resync drives at times on my raid1 and raid5 drives, but I've never had one totally fail (I have had one require reassembly, but I was able to get it back together with mdadm). I just know if I was using some lame-ass hardware fakeraid solution, I'd have lost either my /home partition, perhaps my root partition, or maybe my TV show repository (no biggie). Yay linux.
fsck takes forever on ext3
Oh my god, I sure wish this was faster. It takes forever to check ext3 after 'too many mounts between checks'. And the progress bar will move, then sit and hang forever, then continue. Makes you wonder if it's still working. I'm gonna use JFS for my big-ass data partitions (due to mythtv.org recommendations) and see how that goes.
hard drives don't really consume that much power (7200 RPM's use 5 to 15W each)
I think my server is just fine at 300W with 4 drives, so long as it's a solid 300W. I think my 430 was flaky, and just not providing smooth power. It's really only the nutso video cards that need these 400+ watt power supplies. Hard drives don't really use that much. I don't think anyone really needs a PSU higher than 500W, even with 2 crazy video cards (unless maybe they're both dual-GPU and you're really overclocking with lots of fans and drives).
I'm rockin an vintage PCI Matrox Millenium 2 in my server and it makes me happy.
I love that old video cards never die. I have a junkyard of them. I'm sorta happy I got to use one. I chose it because it doesn't have a GPU heatsink, implying it uses less power, and it is PCI. All the others were AGP or had heatsinks (but are all equally useless for gaming). I should note that my trusty old ATI Mach64 card doesn't seem to work right - the machine boots, but the display either flashes (about 1.5Hz) or doesn't display at all - and if I nudge the card, it sometimes appears. Scary. OK so maybe sometimes old video cards DO die. ;)