Date: Tue, 22 Apr 2003 21:48:35 -0500 From: Josh Paetzel <friar_josh@webwarrior.net> To: Bill Moran <wmoran@potentialtech.com> Cc: questions@freebsd.org Subject: Re: Disk Performance Issues Message-ID: <20030423024835.GN37008@ns1.webwarrior.net> In-Reply-To: <3EA5EC73.1020502@potentialtech.com> References: <20030422170114.GG37008@ns1.webwarrior.net> <3EA5EC73.1020502@potentialtech.com>
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On Tue, Apr 22, 2003 at 09:29:23PM -0400, Bill Moran wrote:
> Josh Paetzel wrote:
> >I've got a FreeBSD 4.8-STABLE system with a Maxtor 6L040J2 ATA/133 7200
> >RPM IDE OS drive in it on a gigabtye GA-7VRXP motherboard. I've also got
> >a pair of Western Digital WD800BB 7200 RPM ATA/100 drives in RAID 1 on an
> >onboard Promise 20276 ATA/133 RAID Controller.
> >
> >atacontrol reports that all the drives are being properly probed:
> >
> >===root@markx ('tty') /storage/os_isos -> atacontrol mode 0
> >Master = UDMA133
> >Slave = ???
> >===root@markx ('tty') /storage/os_isos -> atacontrol mode 1
> >Master = PIO4
> >Slave = PIO4
> >===root@markx ('tty') /storage/os_isos -> atacontrol mode 2
> >Master = UDMA100
> >Slave = ???
> >===root@markx ('tty') /storage/os_isos -> atacontrol mode 3
> >Master = UDMA100
> >Slave = ???
> >
> >
> >My issue is that I'm seeing sustained transfer rates on 600-700 meg files
> >in the 5-6 Meg/second range...about 1/4 of what the drives are capable of.
> >Does anyone have any advice on where to go from here in troubleshooting
> >this issue?
>
> You're reading the specs wrong. That drive is not capable of sustained
> through-
> put of 133mb/s. According to the data sheet, it can only do 44mb/s
> sustained.
> That seems to be about what you're getting. The ATA133 interface will only
> go at 133 until the drive's buffers fill up, then it has to slow down to
> match
> the actual speed the drive can transfer data to/from the platters. Some of
> the
> higher-end SCSI drives are capable of sustained speeds that high, but I
> don't
> know of any 7200 RPM drives that can touch it. Maxtor makes a 15000 RPM
> drive
> that can (purportedly) sustain 75megabytes/sec. (wow!)
>
> --
> Bill Moran
> Potential Technologies
> http://www.potentialtech.com
http://www.dartek.com/printablespecs.cfm?ItemNo=79374
This claims my ATA/100 drives are capable of sustained data transfer of 52.5
Megs/sec. I don't think that's very accurate...most of the benchmarks I've
seen are in the 20-30 Meg/sec range for modern ata/100 and 133 drives. 5
Megs/sec is NOT normal performance however. These numbers I'm throwing about
all refer to susstained transfer rates on large files.
Josh
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