From: Mark Lord <liml@rtr.ca>
To: Richard Scobie <r.scobie@clear.net.nz>
Cc: linux-ide@vger.kernel.org
Subject: Re: SAS v SATA interface performance
Date: Sat, 01 Dec 2007 15:01:40 -0500 [thread overview]
Message-ID: <4751BDA4.9080102@rtr.ca> (raw)
In-Reply-To: <4751B3DA.6030508@clear.net.nz>
Richard Scobie wrote:
>
>
> Greg Freemyer wrote:
>
>> Also, if you have Port Multiplexers (PMPs) in use, that would be
>> interesting to know. I don't even know if PMPs are supported via SAS
>> controllers in 2.6.24 or not. ie. PMP support is new to 2.6.24 and
>> only a few Sata controllers will have PMP support in 2.6.24.
>
> No, port multipliers are not in use here, the technology that SAS uses
> is called port expansion. While I do not know much about the low level
> operational differences, from a performance perspective, this is my
> understanding.
>
> Port multiplication only permits one drive to be accessed at once,
> whereas port expansion allows multiple drives to be accessed
> simultaneously.
..
SATA port multipliers (think, "hub") permit multiple drives
to be active simultaneously.
-ml
next prev parent reply other threads:[~2007-12-01 20:01 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-11-30 19:19 SAS v SATA interface performance Richard Scobie
2007-11-30 21:24 ` Michael Tokarev
2007-11-30 23:17 ` Alan Cox
2007-12-01 7:43 ` Richard Scobie
2007-12-01 14:37 ` Greg Freemyer
2007-12-01 19:19 ` Richard Scobie
2007-12-01 20:01 ` Mark Lord [this message]
2007-12-01 20:40 ` Jeff Garzik
2007-12-01 23:55 ` Richard Scobie
2007-12-02 3:45 ` Mark Lord
2007-12-02 3:49 ` Mark Lord
2007-12-10 7:33 ` Tejun Heo
2007-12-10 14:36 ` Jens Axboe
2007-12-10 16:28 ` Mark Lord
2007-12-10 14:50 ` James Bottomley
2007-12-10 16:32 ` Mark Lord
-- strict thread matches above, loose matches on Subject: below --
2007-12-01 0:04 Richard Scobie
2007-12-01 0:17 ` Alan Cox
2007-12-01 3:06 ` Mark Lord
2007-12-10 7:15 ` Tejun Heo
2007-12-10 16:23 ` Mark Lord
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