From mboxrd@z Thu Jan 1 00:00:00 1970 From: Marc MERLIN Subject: Re: Very long raid5 init/rebuild times Date: Tue, 28 Jan 2014 17:01:59 -0800 Message-ID: <20140129010159.GP28536@merlins.org> References: <20140122174854.GF26014@merlins.org> <52E0807D.2030608@hardwarefreak.com> <20140123091319.GB2306@merlins.org> <52E10A07.3070302@hardwarefreak.com> <20140123210155.GJ10046@merlins.org> <52E1F685.3050300@hardwarefreak.com> <20140125083630.GA7555@merlins.org> <52E76054.5090900@hardwarefreak.com> <20140128165020.GL14998@merlins.org> <52E851C0.50202@hardwarefreak.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <52E851C0.50202@hardwarefreak.com> Sender: linux-raid-owner@vger.kernel.org To: Stan Hoeppner Cc: linux-raid@vger.kernel.org List-Id: linux-raid.ids On Tue, Jan 28, 2014 at 06:56:32PM -0600, Stan Hoeppner wrote: > On 1/28/2014 10:50 AM, Marc MERLIN wrote: > > On Tue, Jan 28, 2014 at 01:46:28AM -0600, Stan Hoeppner wrote: > >>> Today, I don't use PMPs anymore, except for some enclosures where it's easy > >>> to just have one cable and where what you describe would need 5 sata cables > >>> to the enclosure, would it not? > >> > >> No. For external JBOD storage you go with an SAS expander unit instead > >> of a PMP. You have a single SFF 8088 cable to the host which carries 4 > >> SAS/SATA channels, up to 2.4 GB/s with 6G interfaces. > > > > Yeah, I know about those, but I have 5 drives in my enclosures, so that's > > one short :) > > I think you misunderstood. I was referring to a JBOD chassis with SAS > expander, up to 32 drives, typically 12-24 drives with two host or two > daisy chain ports. Maybe an example would help here. > > http://www.newegg.com/Product/Product.aspx?Item=N82E16816133047 Ah, yes, that. So indeed in the price category of a PMP chassis with 5 drives ($150-ish), I haven't found anything that isn't PMP or 5 sata cables. > Yeah, something definitely not right. Your RAID throughput is less than > a single 7.2K SATA drive. It's probably just something funky with that > JBOD chassis. That's also possible. If/when I have time, I'll unplug things and plug the drives directly to the card as well as try another MB. Thanks, Marc -- "A mouse is a device used to point at the xterm you want to type in" - A.S.R. Microsoft is to operating systems .... .... what McDonalds is to gourmet cooking Home page: http://marc.merlins.org/