On Fri, 2010-09-17 at 14:48 -0400, Charles Nadeau wrote: > <snip> > With that said, what's your budget? > I would like to stay below 2000$. I think my system landed <$800 but that was just mobo,cpu,mem & ps, the rest (disk, case, dvd) I had since before. > > > Here are my questions: > > • Is SATA III really worth the price difference knowing that > my server will > > serve at most 3 clients and that I will run RAID 5 or 6? > Right now I am not > > focusing on absolute speed but on stability and > responsiveness. > > My thinking is no. Reson is that while SATA III gives you a > 6BIt/s bus > speed you're still limited by the disk speed. Even if you put > in SDDs > IF I use a SSD, it will be for the boot drive and even for this, I am > not sure if I will. I am using a Seagate Momentus XT in one of my > Ubuntu laptop and it's fast enough for me! I seen this "put OS on SSD" but on a somewhat static system like a file server I'm missing the point. Whatever you read from os disk is when you start up the daemons so it's in cache and writes is just /var/log so where is the gain ? The IO load will be on the data and SSD there could help since it's more random and may not be in cached. > (8T radi5 SDD - guess you need to sell your house for that :) > you Quick reality check, found 250G SSD for $660 so 32x660=$21220 (plus sata cards/port splitters, case, power etc + tax on everything) so you can probably keep your house but not your car. > > I have a 1.5T WD one mirrored with a normal seagate one and > found it to > be very slow. I have it on a server running kvm and when the > different > guests hit different parts of the disk it really hurts. It can > easily be > seen with iostat, seagate lode is 60% while wd is 100%. > > All my disks will be identical so I do not think this will be a > problem. Actually it will, it's just that both are at 100% instead of letting the seagate speed propagate to both. Note - this is for the green drive, WD Black is another story. > > > • Does anybody know a Linux-friendly PCIe SATA controller > that is NOT > > RAID-enabled? > SY-PEX40008, a 4 port PCI express card is what I use. It is > announced as > raid but I use it as a 4 port sata controller. > When looking for sata controllers, don't forget the bus speed. > For > example a 4port sata II will overload PCIe x1 and when using a > raid > > Agreed! > > config you then wonder why you don't get the full speed of the > disk. > > > <snip> > (I may have a > dual port scsi HVD for you to cut down the card count). Loaded > it up > > You already gave me 3 dual ports HVD card! ;-) So then you're set, good. > with 6x2G=12G ram (4G sticks where >$1000 each!) and besides > my green WD > disk that system works fine. > > Knowing that SATA 3 isn't that much worth it and that more ram is > better, I guess then I'll have to look more seriously at the > Supermicro X8SAX motherboard with an i7 processor. I'll also have to > rework a bit my cost structure. If you go down that path, take a good look at xeon and ecc-ram. When I last looked at it the i7 920 had a xeon equivialent where the diff was just ecc ram capable and name. If I did build a server today I would probably go with xeon and ecc even if it cost a few $ more. In the past I had a guest that had a bad habit of coredump now and then. I spent a lot of time on trying to figure out why and even upgraded it to latest version. Then suddenly another guest started to coredump in the same way. Long (months) story short - I had bad memory and did not find out until I did a overnight memcheck. Then I also realized that a db corruption I had might been because of bad memory - not buggy sw. > > /ps > > > > > -- > Charles Nadeau Ph.D. > http://charlesnadeau.blogspot.com/