> -----Original Message----- > From: centos-bounces at centos.org > [mailto:centos-bounces at centos.org] On Behalf Of Ruslan Sivak > Sent: Thursday, May 10, 2007 1:43 AM > To: CentOS mailing list > Subject: Re: [CentOS] Re: Anaconda doesn't support raid10 > > Feizhou wrote: > > Ross S. W. Walker wrote: > >> Hey look at me! I'm top-posting!!! Nanny-nanny-poo-poo > >> > >> Come get me Trolls! > > > > Please do not top post. :) > > > He was probably hinting at me for top posting. > Unfortunately, sometimes > I write from the blackberry, which only allows top posting. > Take it up > with RIM. > > > >> SATA drives typically do 60-70MBs, interleaved you > >> should see 120-140MB/s on sequential. Random IO on SATA > >> usually sucks too badly to even talk about... > > > > Eh? It cannot be worse than PATA drives now can it? > > _______________________________________________ > > Probably not, but is SATA really much worse then SCSI or SAS? I did > some testing on a dell PE 2950 of 750GB SATA's vs SAS and > SCSI drives, > and the SATA drives seem to be faster at least at first > glance. I don't > have good numbers from the SCSI tests, but at least for > sequantial, I'm > getting a better speed off the SATAs. SATA and SCSI/SAS should give comparable single work-load sequential numbers, but most SCSI/SAS have better seek times so random IO will be better on those. Also SCSI/SAS support tagged command queuing, which allows multiple overlapping IOs so you will tend to see better mixed workload performance compared to SATA (multi-user environment). Having said that some of the new SATA models that support NCQ, the SATA version of TCQ, and that use some of the same SCSI/SAS onboard processing (Western Digital Raptors) can approach or equal SCSI/SAS mixed load performance, but their price also approaches or equals SCSI/SAS and their spindle speeds still do not top 10K so random will not be as good. -Ross ______________________________________________________________________ This e-mail, and any attachments thereto, is intended only for use by the addressee(s) named herein and may contain legally privileged and/or confidential information. If you are not the intended recipient of this e-mail, you are hereby notified that any dissemination, distribution or copying of this e-mail, and any attachments thereto, is strictly prohibited. If you have received this e-mail in error, please immediately notify the sender and permanently delete the original and any copy or printout thereof.