On Fri, 2010-09-17 at 12:51 -0400, Charles Nadeau wrote: > Hello, > > I am looking to replace my 5 years old file server (based on a AMD Duron > 2800) with something more powerful and I’d like to pick the brains of fellow > Linux user on this mailing list regarding a few questions I have. > I haven't completely decided what I will build but I am leaning toward an > AMD-based solution because SATA III on the SB850 chipset seems to be > integrated more tightly than the Marvell one the Intel platform. Nothing is > set in stone yet. I will use either Ubuntu Server or Gentoo as my > distribution. > > My requirements are: > • Need to work reliably 24/7 with a minimum of maintenance. > • Need 8TB of storage (to be expanded in the future using an additional PCIe > SATA controller) to be exported using NFS and Samba (for my wife XP > laptops). I will use RAID 5 or 6. > • Support for my 2 SCSI cards in PCI slots to support my tape libraries > (using Bacula). > • I may also use the machine to run a few virtual machines for testing. > (using VirtualBox) You forgot one requirement, should be reasonable price for home use. With that said, what's your budget? > 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 (8T radi5 SDD - guess you need to sell your house for that :) you may pass SATA II but then we hit other limits like io bus and cpue + yhe output is at best Gbit network so what would you do with so much disk speed. If you plan on putting up port splitters or so then it might be worth it. > • Has anybody used “Green” drives (Samsung, WD, Seagate) with Linux software > RAID? I read that “Green” drives in RAID may be problematic because the TLER > delay is too short. The RAID may mistakenly consider a drive to have failed > and kick it out of the array. 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%. > • 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 config you then wonder why you don't get the full speed of the disk. <snip> > • How much RAM should I get for a file server like the one I am building? > Will more RAM means more cache and better performance or with a small number > of clients it doesn’t really matter? Is ECC-RAM really important in my > situation? More ram is almost always better and when you run a few virtual guests you run out of ram fast. ECC-RAM importance - depends on how important your data/system is but it will cost you extra all the way from cpu (you need Xeon or Opteron) and mobo to ram. > • Is the number of cores really important for a file server? If I am to go > with AMD, I am leaning toward either the Phenom X6 1055T or the Phenom X4 > 945. Are these overkill for a file server? I will not overclock my > processor. You did mention virtual guests and then core count is good. If you stick with file server 2 cores should be enough and put your money on the ram. Since my home system is more of a virtual host then a file server (but one of the guests is a fileserver) I need more ram. Going with AMD I hit a limit on the consumer side, mobos have only 4 sticks or a 4x pricetag. Because of that I did go with Intel i7 920 since with the tribus I then get 6 sticks. My mobo is MSI MS-7522 and it has both PCI and PCIe slots (I may have a dual port scsi HVD for you to cut down the card count). Loaded it up with 6x2G=12G ram (4G sticks where >$1000 each!) and besides my green WD disk that system works fine. /ps