On 05/02/14 02:03, Joseph Bishay wrote: >> IME the best thing you can do for an LTSP server is add RAM. You >> probably don't need it for applications but Linux will take whatever is >> unused and allocate it for cache and buffers, and that all turns into speed. > I've currently got a custom built i7 tower with 12 GB of ram. The > other server is a HP Proliant with 4 GB but I can of course install > more. The issue is that hardware for the proliant is way more > expensive than the i7 so before I invest in it I wanted an idea if it > would actually help. Since the i7 (almost certainly) cannot have ECC memory I'd certainly think twice about using that for a server, or for anything else that's important for that matter. Google published a study into memory reliability and.. well, it's not pretty. And they tested server-grade ECC memory, which is presumably higher quality than non-ECC sticks... Go for Xeons, Opterons or AM2/3/3+ Athlon/Phenom with a suitable board (afaik only Asus) to get ECC support. The extra cost of ECC over non-ECC is almost nothing, but unfortunately Intel cripples the i* CPUs to remove this feature, so that you have to get a Xeon instead. If HP tries to rip you off on part prices I'd just get them elsewhere. They probably do, I'm quite sure those 350$ SAS drives you mention are 7.2krpm.. no idea why anyone would make, let alone buy, such drives, unless replacing breakage.
>> Next I would look at a faster NIC and faster disks. > Both have good NICs but the disks are an interesting area. Our > existing server has SATA III terabyte drives. The proliant takes > hot-swappable SAS-2 2/5" drives and I'd need to purchase 1 TB drives. > Each drive is around $700 and I'd need two. I'm 99% sure you can simply take a SATA drive and connect it to an SAS port (but not the other way round I don't think). Ofc if you buy normal 1TB 5.4krpm/7.2krpm drives at 50 or 100 bucks each you're not gonna get the performance that a 10krpm drive for 200 or 400$ gives. That is assuming those expensive HP drives are even 10krpm - if not then IMHO it's literally throwing money out of the window to pay a 200% premium for a minor difference in connection method. Btw you can get 10krpm SATA with 1TB for 175€ which is roughly 200$. Then again if IO-performance is an issue IMHO going for faster spinning rust is very rarely sensible, just get an SSD (it can also be used as cache for the spinning rust). >> I would only upgrade the CPU if I find it is frequently busy. When I do >> I start with PassMark's database to get an idea of relative CPU performance: >> http://www.cpubenchmark.net/cpu_list.php > Thanks for that link - it is a great resource. > > Interestingly, according to that site, a single i7 chip outranks dual > Xeon chips. I was rather surprised but the results are: > Intel Core i7 920 @ 2.67GHz: 5004 (higher better) 242 (lower > better) 17.56 (higher better) $285.00 > [Dual CPU] Intel Xeon X5260 @ 3.33GHz: 4800 124 2.82 $1,702.00* > > The reason I'm thinking about the new machine is that the tower has no > real redundancy and everything depends on it. And I have two > identical Proliant machines that I can use but the drives and RAM are > rather expensive so wanted to get feedback first. > > Thanks! > Joseph Well those Xeons are dual cores, the i7 is a quad.. so you get (pretty much) identical total number of clocks. Good Luck, Steffen ------------------------------------------------------------------------------ Managing the Performance of Cloud-Based Applications Take advantage of what the Cloud has to offer - Avoid Common Pitfalls. Read the Whitepaper. http://pubads.g.doubleclick.net/gampad/clk?id=121051231&iu=/4140/ostg.clktrk _____________________________________________________________________ Ltsp-discuss mailing list. To un-subscribe, or change prefs, goto: https://lists.sourceforge.net/lists/listinfo/ltsp-discuss For additional LTSP help, try #ltsp channel on irc.freenode.net
