On Sun, 2 Feb 2003, [EMAIL PROTECTED] said: > Hi > > > > From: Julius Szelagiewicz <[EMAIL PROTECTED]> > > > > also, i was mistaken when i said that only the memory size was wrong > > > > with system. the processor is inadequate too: Intel Pentium 4 > > > > processor 2.4GHz with 512K enhanced cache. it would be better to have > > > > 2 1.3GHz piii processors, or at least one xeon xp, or p4 3.06 with > > > > multipath capabilty. > > > > > > Have you tried a dual Athlon box ? About $1k will do motherboard, dual > > > 2100+ processors, case and associated stuff. If you choose a > > > motherboard with quad memory slots, you can buy 4* the cheaper 1GB. > > > In my experience, that'll outperform a single P4 processor handily. > > > Adding a gigabit card for the client side interface isn't much either. > > > > I'm a strong advocate for SCSI for multi-user systems. GB for GB it's > > more expensive, so I tend to use slightly older, smaller capacity drives. > > Although IDE has largely caught up in terms of i/o bw, the SCSI command > > queuing advantage has yet to be matched, making for much smoother > > server performance. Of course also off-loads a lot of the disk i/o burden > > from the CPU, so it's like having a faster CPU. > > I'm looking for info, not a flame war!
<jaw drops> ?? Then why are you making a pre-emptive strike? I'm just stating opinions based on my experiences. Take them with a grain of salt. The thought of starting a flame war hadn't been further from my mind. > In my experience SCSI offers no advantages. > My bus-mastering IDE does a sustained 40M/sec (1G files) As I attempted to say, but probably not as clearly as I had intended, with the current generation of hd's the difference in throughput has diminshed or perhaps vanished. The difference lies in the SCSI command queuing off-loading the CPU. My most recent experience in comparing the two disk types was about 3 yrs ago, with a PII-350, running novell emulation for a lab of 20 mostly 386 machines booting from floppy, running W31 / MS-Office on a 10b2 LAN - definitely low budget. A single Linux box replaced 2 Novell 3.11 boxes. I first tried an IDE (the mobo probably wasn't equipped with anything above ATA-33, if that), and net performance was so slow as to be unworkable - there was a one or two second pause after each keystroke in MS-Word as the temp file would get updated, and connections timing out. After switching to SCSI switched to SCSI, it became a workable system. > Subjective experience, and iozone benchmarks show little advantage of one > or the other (SCSI-Box: Compaq ProLiant UW SCSI vs no-name Athelon both > around 1GHz). (compaq is *NOISY*) > > Install RH from CD is about the same time. > > Where does the SCSI advantage show (I/O benchmarks are on a busy server) > > Also 'older' discs are slow, so double negative advantage. > (Older expensive baracuda multimedia seagate discs managed 10M/sec sustained) I think that most of the gains in throughput are attributable to increases in data density on the drives more than any other single factor. But I tried to make the point that the advantage lies in multitasking capability, not throughput. So I would deduce that the advantage would be more apparent on a multi-user system than on a single user system. ================================================================ A quick and dirty test via hdparm on my home system yields the following results: 80 GB ATA-100 # hdparm -t /dev/hdc /dev/hdc: Timing buffered disk reads: 64 MB in 1.98 seconds = 32.32 MB/sec ---------------------- 9.1 GB SCSI Ultra wide (U160) # hdparm -t /dev/sda /dev/sda: Timing buffered disk reads: 64 MB in 2.31 seconds = 27.71 MB/sec A quick calculation shows that the ATA disk with 8.8 times (i.e., 880%) the data density yields a throughput improvement of 16%. ================================================================ All that said, perhaps it's time to try an ATA-100 in one of the boxes with a currently available mobo to see what kind of performance differences there are with the current hardware. I hope I'll find that I can justify dropping SCSI, and saving the added expense. ---------------------------------------------------------------- John Karns [EMAIL PROTECTED] ------------------------------------------------------- This SF.NET email is sponsored by: SourceForge Enterprise Edition + IBM + LinuxWorld = Something 2 See! http://www.vasoftware.com _____________________________________________________________________ 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
