Date: Tue, 9 Feb 2010 11:29:50 -0500 From: "Dan Langille" <dan@langille.org> To: "Tom Evans" <tevans.uk@googlemail.com> Cc: Charles Sprickman <spork@bway.net>, FreeBSD Stable <freebsd-stable@freebsd.org>, Dan Langille <dan@langille.org> Subject: Re: hardware for home use large storage Message-ID: <7118399d109e0c1849ae17ffa8ee9c66.squirrel@nyi.unixathome.org> In-Reply-To: <2e027be01002090716y77213c45pb937e22151a2c238@mail.gmail.com> References: <4B6F9A8D.4050907@langille.org> <alpine.OSX.2.00.1002090103520.982@hotlap.local> <2e027be01002090451w2b4506a0ofb5ab55c647540a@mail.gmail.com> <a586d9acd7436f3fdab4f88114309aef.squirrel@nyi.unixathome.org> <2e027be01002090609y28be404dl1bb610d047b15f9b@mail.gmail.com> <f6a0ed0187f2e747696805773154cad9.squirrel@nyi.unixathome.org> <2e027be01002090716y77213c45pb937e22151a2c238@mail.gmail.com>
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On Tue, February 9, 2010 10:16 am, Tom Evans wrote: > On Tue, Feb 9, 2010 at 3:01 PM, Dan Langille <dan@langille.org> wrote: >> >> On Tue, February 9, 2010 9:09 am, Tom Evans wrote: >>> On Tue, Feb 9, 2010 at 1:45 PM, Dan Langille <dan@langille.org> wrote: >>> One thing to point out about using a PM like this: you won't get >>> fantastic bandwidth out of it. For my needs (home storage server), >>> this really doesn't matter, I just want oodles of online storage, with >>> redundancy and reliability. >> >> >> A PM? What's that? >> >> Yes, my priority is reliable storage. Speed is secondary. >> >> What bandwidth are you getting? >> > > PM = Port Multiplier > > I'm getting disk speed, as I only have one device behind the PM > currently (just making sure it works properly :). The limits are that > the link from siis to the PM is SATA (3Gb/s, 375MB/s), and the siis > sits on a PCIe 1x bus (2Gb/s, 250 MB/s), so the bandwidth from that is > shared amongst the up-to 5 disks behind the PM. > > Writing from /dev/zero to the pool, I get around 120MB/s. Reading from > the pool, and writing to /dev/null, I get around 170 MB/s. > That leads me to conclude that a number of SATA cards is better than a port multiplier. But the impression I'm getting is that few of these work well with FreeBSD. Which is odd... I thought these cards would merely present the HDD to the hardware and no diver was required. As opposed to RAID cards for which OS-specific drivers are required. -- Dan Langille -- http://langille.org/
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