Although my initial request for info was to find out if any mobo based ATA RAID chip sets were credible, that thread has now segued a bit but I'll respond. BTW - It does look like I'll get a sample 3WARE and RAIDCORE to test with since it doesn't look good for the mobo RAID chips given the responses. > Kent wrote - Don't blame Linux for the sins of other OSs. I'm not blaming anything - I'm stating the obvious. All OS's have bugs. The software flashed into a RAID chip can also have bugs, but in the 20+ years of setting up SCSI RAID arrays, I've never had a RAID controller fail either via hardware or its eprom software. Backplanes have failed, which is why I avoid them, but the controllers and their on board chips have never given me cause for concern. The O/S is simply a richer source of failure. RAID logic has been tested over lots of years and is a narrowly focused collection of code. When its burned into a chip, its largely immune from corruption by viruses, rogue ring 0 code, and even hackers. ATA RAID logic has to be very similar to SCSI RAID logic at least at some level. Therefore ATA RAID inherits credibility from the SCSI work done that preceded it as far as I'm concerned. Your description of how RAID works also applies to the hardware RAID variety so its a wash. > Kent wrote - I once had a disk die ... and I never noticed ...until the next morning ... That's a problem. Many hardware RAID controllers scream when something goes wrong. The machine beeps, whistles or in some way is annoying to attract attention. It allerts the sysadmin to a problem, the solution to which is varied. It can be to do nothing if he has a hot spare (which doesn't require a backplane) that's been in the machine since array creation, or it can be to phone in an order for a replacement drive. It depends on the situation. > Kent wrote - Linux software raid 1 is even bootable--though getting your BIOS to try more booting from than one disk might be tricky Hardware RAID is always bootable (given you got the right controller in the first place) even if I remove a physical drive in a RAID 1 or 5 array. No worries about the machines BIOS not wanting to use an alternate boot volume because it always uses the same boot volume - the array as the array controller wants to present it, even in a degraded state. > Kent wrote - One key point of raid 1 is reliability, and reliability likes simplicity and eliminating single points of failure I agree in principle. However, I also like redundant power supplies. They are far more complex than a non redundant version, but I've also never seen one fail as a whole in 20+ years. A portion of a redundant supply may fail but the O/S on the machine never noticed. So, reliability and simplicity do not go hand in hand 100% of the time. > Kent wrote - and getting things back up and running quick when they do fail. With a hot spare I am forced do absolutely nothing when a drive fails. If I want, I can replace the failed drive whenever I get around to it. If the box is already old enough and due to be replace in 12 to 18 months, I wouldn't bother. I'd let it run with no hot spare, but with complete RAID redundancy. One more drive can fail and I'm still in good shape. > Kent wrote - Are you going to quit running any software? No - I have no intention of scrapping my servers in favor of a Big Chief Tablet and a number 2 pencil. > Kent wrote - The software in Linux raid code is very well tested by now--will that be true of the embedded software in your "hardware" controller? I believe the RAID knowledge base Adaptec and its offspring RAIDCORE and to some extent 3WARE are using predated Linux by at least a decade. I trust them more. > Kent wrote - Will needed firmware updates be as promptly released? To date, I've never cared if they released firmare updates to the RAID controllers I've used. In 20+ years, I've never flashed an operational servers RAID proms. I've never had to - the code has been that good. I usually flash the mobo BIOS and the RAID BIOS to the most recent versions before I installand then thoroughly test the O/S & RAID combination. That's before it goes into production. I have patched vendors RAID drivers for a particular O/S on a production server, but was forced into that only once. -- Bill Gradwohl YCC (817) 224-9400 x211 www.ycc.com SPAMstomper Protected E-mail www.stomperware.com
