*BSD News Article 87952


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From: snowdog@charm.net (Sean Rolinson)
Newsgroups: comp.os.linux.misc,comp.os.linux.networking,comp.os.linux.setup,comp.unix.bsd.bsdi.misc,comp.unix.bsd.misc
Subject: Re: IDE vs SCSI (was Re: Linux vs BSD)
Date: Fri, 31 Jan 1997 20:31:43 GMT
Organization: Charm Net Inc.
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Message-ID: <32f25333.82521689@news.charm.net>
References: <32DFFEAB.7704@usa.net> <5c3k6o$qro@lynx.dac.neu.edu> <873evtxn6t.fsf@localhost.xs4all.nl> <87k9p4rckd.fsf_-_@murkwood.gaffaneys.com> <5cogse$3ldq@usenet1y.prodigy.net>
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Hello,

I work as a Systems Administrator for an ISP and we have roughly 30
different computers in production.  The majority of them use SCSI
drives and a handful use IDE.  We use the Adaptec 2940UW and the
Seagate Barracuda 2 and 4 Gig drives and recently the Hawk (Ultra
Wide, 1/2 height 4 GIG, nice drive!)  

I do not know the internal workings of the SCSI and IDE drives, but I
can tell you that the SCSI drives seem to provide better throughput
and overall speed as compared to our IDE drives.  

Our news server is running off a bunch of 2 Gig SCSI drives and I
would not dare attempt this with IDE (especially since quantity of
drives becomes a real issue).  We are generally very happy with our
news server and it is quite fast.  

The discussion that we have going on now, is whether 4 2 Gig drives is
faster than 2 4 Gig drives, and will RAID improve the performance of
the drives?  What we found from http://www.tesys.com/bench.shtml is
that RAID 5 (using a DPT controller) is slower than even using plain
ole standalone disks, and that using BSDI 3.0 software with dual
controller striping, they were able to get speeds in excess of 20MB's
per seconds (actual).  

I do not know of any IDE drives that could make that comparison.
Although, you are dealing with price/performance, and SCSI is a bit
more expensive in general. (But this makes me a bit more excited about
BSDI 3.0).    

Sean Rolinson
snowdog@charm.net

davidsen@tmr.com (bill davidsen) once said:

> In article <87k9p4rckd.fsf_-_@murkwood.gaffaneys.com>,
> Zach Heilig  <zach@blizzard.gaffaneys.com> wrote:
> | Probably little disagreement here, except among the clueless :-) This
> | is my explanation why IDE will always be slower than SCSI (and why
> | SCSI is usually more expensive).
> | 
> | Peter Mutsaers <plm@xs4all.nl> writes:
> | 
> | > Todays IDE drives are not much slower than SCSI drives
> | 
> | [snipped]
> | 
> | There probably aren't any performance differences between IDE and SCSI
> | hardware.  The differences come in when you compare the interfaces
> | themselves.
> 
> The limiting factor is the speed of the bits coming off the platter
> for a single drive. The interface can keep up with that, even on a 8
> bit card with programmed i/o. Sustained i/o, at any rate, cache here
> and there makes it meaningless to measure anything else.
> 
> As you say, the drives are the same.
> -- 
> bill davidsen (davidsen@tmr.com)
>   Windows NT is like a doctoral thesis; it contains a wealth of
> interesting features and ideas, some of which could be extracted
> from the proof of concept and used in a real operating system.