visit http://www.it.iitb.ac.in/~lcc/presentaions/nilesh/pics/page_01.htm for all u want to know bye i hope it will help u ashvin > On Thu, 21 Aug 2003 [EMAIL PROTECTED] wrote: > >>Hi >> >>> > > * IDE drives die around 10 concurrent users. Fast SCSI or FC >>> drives are >>> > > manditory for a large number of concurrent users. The faster >>> the better. >>> > >>> > Can anyone else comment on the disk requirements ? >>> > >>> > Does more RAM help ? >>> > >>> > What, exactly, is so great about SCSI ? >>> > >>> > The platters turn at the same speed - is it the elevator algorithm >>> seek and the out-of-order replies ? >>> > >>> > I /really/ don't want to have to go the SCSI route. >>> > >>> > I tried Software RAID5, but the rebuild after a power cut was >>> painful. >>> Andy, going backwards: >>> trust us, the "grownups" - you very, very much *want* to go the >>> SCSI route. There are reasons for higher prices - the disk >>> electronics are way more advanced, the request queueing really works, >>> the wide data path allows for *sustained* high throughput, the >>> otpitmized head movement traslates into faster reads and writes and >>> into longer hardware life. And, no, serial ata is *not* as good as >>> scsi. >>> software raid - try harder, or go hardware raid with hot swappable >>> drives (scsi, of course :-) >>> more ram helps big time - ram is good, more ram is even gooder. >> >><smiles> >>> trust us, the "grownups" - you very, very much *want* to go the >> >>Please give info. please: >>I tested a compaq proliant with UW SCSI, 10 lts workstations >>against a ATA100 IDE. >>hdparm -t -T /dev/hda <sda> gives a slight edge to the IDE. >>For most part the two machines felt the same. >> >>I missed the opportunity to use the SCSI during a disk-disk backup >> where the IDE was noticible (making the system sluggish). >> >>SCSI is a lot more cost-and-hassle than IDE, I'll do it if there is a >> clear benefit vs hearsay, but it's hard to find someone to say >> >>I used to use IDE and when I changed to SCSI these marvelous things >> happened >> >>rather than >> >>I've made up my mind about SCSI, please don't try to confuse me with >> facts >> >>so please ... >>James > > [ DISCLAIMER: stated statistics are from memory, but are in the ballpark > ] > > Benchmarks such as "hdparm -t -T /dev/drive" do not show the difference > between SCSI and IDE. > > I once had the chance to help debug a decent server with a fast UDMA 100 > IDE drive that was falling over dead at about 15 concurrent sessions. > > We slapped in an _OLD_ ULTRA2 SCSI drive and it ran ok with 30 > concurrent sessions. [actually, it is still running fine on the old > SCSI drive, I never asked for it back...] > > "hdparm -Tt" said that the IDE drive was twice as fast as the SCSI > drive. > > bonnie++ (a hard drive benchmark utility) said that the IDE drive was > somewhere around 30% faster than the SCSI drive. > > Yet the "slow" SCSI drive powered more than twice as many concurrent > clients as the "fast" IDE drive. > > We put the IDE drive back in and added a second processor and more > memory, without making much difference. The IDE drive was definately the > bottleneck. > > Most of the hard drive utilities I've seen don't do a good job of > stressing a hard drive in the same patterns that a terminal server does. > > IDE drives do a great job with linear access (such as tested by hdparm) > but completely fall part when faced with a huge number of small, random > reads and writes. Beyond a certain stress point, IDE drives just grind > themselves to a halt. SCSI will decay gracefully. I've seen this many, > many times. > > If IDE is currently working for you, great (but plan for it to fall > apart if usage of terminal server increases). > > If you are trying to size a new server and are not sure whether to buy > IDE or SCSI, go for SCSI. > > -Eric > > > > ------------------------------------------------------- > This SF.net email is sponsored by: VM Ware > With VMware you can run multiple operating systems on a single machine. > WITHOUT REBOOTING! Mix Linux / Windows / Novell virtual machines > at the same time. Free trial click > here:http://www.vmware.com/wl/offer/358/0 > _____________________________________________________________________ > 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
-- Yours Sincerely, Ashvin Gami, Senior Graduate, B.Tech.(Elec.Engg.), IIT Mumbai. ------------------------------------------------------- This SF.net email is sponsored by: VM Ware With VMware you can run multiple operating systems on a single machine. WITHOUT REBOOTING! Mix Linux / Windows / Novell virtual machines at the same time. Free trial click here:http://www.vmware.com/wl/offer/358/0 _____________________________________________________________________ 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
