Date: Mon, 27 Jun 2005 13:48:44 +1000 From: Brett Wildermoth <B.Wildermoth@griffith.edu.au> To: freebsd-stable@freebsd.org Subject: Re: SATA vs SCSI ... Message-ID: <200506271348.53375.B.Wildermoth@griffith.edu.au> In-Reply-To: <20050627031918.GA20199@tmn.ru> References: <20050626233114.G57847@ganymede.hub.org> <20050627031918.GA20199@tmn.ru>
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--nextPart4498072.EARrkH8a5P Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Content-Disposition: inline One other point worth mentioning is that on SATA all transactions are host= =20 generated, while with SCSI devices any device can start a transaction.=20 Transactions can be interleaved better resulting in a higher average=20 throughput. On Mon, 27 Jun 2005 01:19 pm, owner-freebsd-stable@freebsd.org wrote: > On Sun, Jun 26, 2005 at 11:34:22PM -0300, Marc G. Fournier wrote: > > looking at the specs between two cards, the SATA card(s) seem to rate > > ~100-150MB/s on each channel (if I'm reading right), with both the 3Ware > > and ICP cards having 4 individual channels ... looking at the SCSI card= s, > > they are rated at 320MB/s, but that is total for the SCSI bus itself, > > right? > > It is dependant of the card too. You can get a 3 channel Ultra320 card for > 3 drive RAID 5... > > > So, if I have three drives on a SCSI bus, each 'maxing out evenly', I'd > > be cap'd at about the same 100MB/s per drive, no? > > > > In fact, looking at the SATA 2.x specs, each chanell there is rated at > > 300MB/s, which, again, if I could 'max out evenly', could seriously blow > > away the SCSI bus itself ... > > That is a theory... > > > *If* I'm reading this right ... ? > > And now from my practice: > > 1) You CAN'T get maximal throuput from 150/160 MB/s bus - the is no such > drives today at the market. > > 2) Avg. seek and access time of 7200 SATA drives are FAR BELOW such of old > Seagate Cheetah/Maxtor Athlas 10K. So is a situation with a WD Raptor 10K > SATA too - they are SLOWER! (I'm not shure why, but from my test: > > 2xPIII-1.4/1G RAM/2x36G Cheeta 10K in RAID 1 (AMR Express; One U160 > channel) ws. > 2xXeon 3.0/2G RAM/2x72G Raptor in RAID 1 (Intel SRCS16; Separate SATA-150 > channel for each drive) > > Ports three checkout is about 20% faster on the first comp. > > As an result: If you need to have FAST disk subsystem - buy SCSI. If you > need large storage or you don't want to pay to much money - buy SATA. > > Best Ragards, > > Serg N. Voronkov, > Sibitex JSC. > _______________________________________________ > freebsd-stable@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-stable > To unsubscribe, send any mail to "freebsd-stable-unsubscribe@freebsd.org" =2D-=20 =2D------------------------------------------------------------------ Brett Wildermoth BEng(ME) MPhil Lecturer / PhD Student School of Microelectronic Engineering Faculty of Engineering and Info. Tech. Ph. +61 7 3875 5063, Fax. +61 7 3875 5384 Email. B.Wildermoth@grifith.edu.au =2D------------------------------------------------------------------ --nextPart4498072.EARrkH8a5P Content-Type: application/pgp-signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.1 (FreeBSD) iD8DBQBCv3clbSsZm/bQWSwRAon+AKCSUirKNRM1BJj3N8RLd8qk6t/tDgCgny9n I4CLUN6L7razijKXDsnE5pE= =CtE2 -----END PGP SIGNATURE----- --nextPart4498072.EARrkH8a5P--
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