On Fri, Sep 17, 2010 at 1:59 PM, Peter Sjoberg <peters-oclug [ at ] techwiz [ dot ] ca>wrote: > 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? > I would like to stay below 2000$. > > > 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! > (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%. > All my disks will be identical so I do not think this will be a problem. > > > • 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> > > • 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 > You already gave me 3 dual ports HVD card! ;-) > 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. Thanks! Charles > > /ps > > -- Charles Nadeau Ph.D. http://charlesnadeau.blogspot.com/