On Sun, Nov 22, 2009 at 12:43 PM, R.G. Keen <k...@geofex.com> wrote: > Thanks for replying! I did look into that. The AMD design was my second > choice. > > It was : > AMD Athlon II X2 240e (to get low power; the dual core and lack of L3 help > there) > ASUS motherboard (see considerations below) > Cheap VGA? LAN card? This is the mire that ultimately bogged down this one. > > Given that data integrity drove me to Opensolaris and zfs for a file server > instead of to a simple NAS box which would have been cheaper and easier, I > reasoned as follows: > - yep, raidz2 is going to meet data integrity better than raidz; so I need > plug in capacity for six disks minimum, that gets to raidz2 with the lowest > number of data integrity issues based on disk failure (I think...) > - there are six-SATA and more motherboards which exist, so there is a > premium on using one of these MBs if opensolaris supports the SATA > controller on the MB, instead of finding and buying one or more disk > controller cards. The disk card which seems most supported and cheapest > seems to be the Supermicro PCI-x eight-SATA version for $100. One could > argue that two-three cheaper cards would get you under $100, but that then > begs the issue of complexity, number of slots on the MB, and additional > electrical power use, which is a secondary consideration, but one which is > an obvious issue with the more cards stuffed into the box. So a six-SATA > native controller is a Good Thing > - back at data integrity, a motherboard failure is a problem too; a > well-trusted and well tested MB is a plus. I took that to mean "don't buy a > MB with "overclocking" mentioned as a plus for it, and don't bother with all > the fancy onboard widgies you can get. My personal positive experiences have > been with ASUS, Gigabyte, and Intel. I have had motheboard deaths and > erratic behavior with ECS, FCI, and DFI. Haven't used a Supermicro, but they > seem to be highly recommended. > - gotta have ECC RAM on the MB > - amount of memory is pretty much a don't care these days; 4gb to 8gb are > probably fine, maybe even less is OK. > - number of slots is only an issue if I have to use external disk cards. > This might be an issue if I was trying to get over a few TB of server > storage, but I'm pretty happy with under 10TB. If I was trying to fill up a > 20-30 disk array, I'd have different answers. I can't afford that many > disks. So a 6-SATA MB is a good compromise. > - intel vs AMD CPUs is a don't-care to a first approximation. Both support > 64bit, both have ECC support in some flavors. This means select based on MB > features, not architecture. At a secondary level, AMD seems to be cheaper > and perhaps lower power if you get especially the newly announced "e" > versions, notably the Athlon II X2 240e. But saving $100 on a processor or > 20W on the power budget isn't worth not having the right number of disks on > the MB or hot having chipset drivers be available. I've written device > drivers, years ago. I used to wrestle in college, too, but I wouldn't want > to walk back out on a mat at this point in my life either... 8-) > > On the AMD side of things, I'd have gone with the X2 240e I mentioned. It's > a 45nm chip, AM2+/AM3 socket, 45W TDP. Probably $60-70 if I could find one > in stock; it's new enough that it's hard to find. The competing intel chip > is the dual processor Xeon E3110 at 65W, for $180. So AMD saves me $100 > right off the bat. > > But what motherboard? All the AMD chips have ECC support inside their > chipsets, so all we have to do is find a MB which lets that work. There are > MBs around which note that they'll take ECC or non-ECC memory. The question > is whether they *do* anything when there's an ECC fault. I went through the > entire Gigabyte line and could find no BIOS support for ECC > reporting/action. They may let you use the memory, but they don't actually > do anything if there's a fault. This is very much like taking the spare tire > off your car, but feeling OK because there's a place where one could go, to > me at least. > > That gets me down to Intel, ASUS, and Supermicro boards for AMD. ...oops, > there are remarkably few intel-brand MBs which support AMD chips! OK, ASUS > and Supermicro. In the ASUS line, AMD suggests only the ASUS M4A78T-E for > the Athlon II X2. This has only 5 SATA (bad!) but two PCIex X8 slots > (good!). The sixth SATA is routed to an ESATA port on the back of the > motherboard. Clumsy, but could be usable, I guess. The chipset is the AMD > 790GX and SB750, with Atheros (?)L1E LAN and Radeon HD3300 graphics. > Downloading and checking the user's manual shows that ECC can indeed be set > to ... something... which might work. > > And here's where I diverged from this stack. I had dim results trying to > find confirmation that the chipsets were supported under opensolaris. I got > some indication they did, some that they didn't, or that they had problems. > Apparently one could insert a VGA card and a LAN card and get around that. I > ... think ... the SATA controller works under opensolaris, and you could run > an ESATA cable back through a hole in the case to get a sixth SATA disk. > > This uncertainty is what pushed me back to the intel Xeon stack. > > I've thrashed this pretty hard for several weeks now. > > Someone can correct me if I'm wrong... but I believe that opensolaris can do the ECC scrubbing in software even of the motherboard BIOS doesn't support it.
-- --Tim
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