Date: Wed, 5 Feb 2014 04:24:33 -0500 From: Rich <rincebrain@gmail.com> To: Daniel Kalchev <daniel@digsys.bg> Cc: freebsd-fs <freebsd-fs@freebsd.org> Subject: Re: practical maximum number of drives Message-ID: <CAOeNLuohed9PB7SXNvB40N9-8Cna6DOg0mF5vXn48%2B0rTF3Dog@mail.gmail.com> In-Reply-To: <52F1FBBA.1000909@digsys.bg> References: <52F1BDA4.6090504@physics.umn.edu> <7D20F45E-24BC-4595-833E-4276B4CDC2E3@gmail.com> <52F1DEBC.9020304@digsys.bg> <CAOeNLuqhT1y7rzA2=80jzXByrYy0cbCTaFv-5=X1KOnkFtRN8Q@mail.gmail.com> <52F1FBBA.1000909@digsys.bg>
next in thread | previous in thread | raw e-mail | index | archive | help
http://www.lsi.com/products/host-bus-adapters/pages/lsi-sas-9200-8e.aspx Claims 512. http://www.lsi.com/products/host-bus-adapters/pages/lsi-sas-9211-4i.aspx claims 256. I'm really extraordinarily curious to see what would happen, but do not have >512 unused drives I could attach to a single HBA to find out...easily. I have >256, but since all the stuff I can find other than SM's documentation claims 512 for the SAS2008, that would only refute their statement, not LSI's. - Rich On Wed, Feb 5, 2014 at 3:52 AM, Daniel Kalchev <daniel@digsys.bg> wrote: > Ok, two things. > > First, it was a typo -- the number is 122 devices and I actually got it from > the likes of this FAQ entry: > http://www.supermicro.com/support/faqs/faq.cfm?faq=10004 > I never use these for anything other than HBA. > > It is interesting to see that LSI claims 3000 devices. Might be, firmware > has changed? Or there are different variations of the chip/implementation? > > Daniel > > > On 05.02.14 10:08, Rich wrote: >> >> The SAS2008 has a limit of 112 drives? >> >> >> http://www.lsi.com/downloads/Public/SAS%20ICs/LSISAS2008/SCG_LSISAS2008_PB_043009.pdf >> claims "up to 3000 devices." >> >> SAS2008 is a PCIe gen 2 x8 chip. >> >> I suspect the bottleneck order would go SAS expander then SAS2008 then >> PCIe. >> >> - Rich >> >> On Wed, Feb 5, 2014 at 1:48 AM, Daniel Kalchev <daniel@digsys.bg> wrote: >>> >>> I also wonder how you managed to go over the LSI2008's limit of 112 >>> drives... >>> >>> >>> On 05.02.14 07:36, aurfalien wrote: >>>> >>>> Hi Graham, >>>> >>>> When you say behaved better with 1 HBA, what were the issues that made >>>> you >>>> go that route? >>>> >>>> Also, curious that you have that many drives on 1 PCI card, is it PCI 3 >>>> etc... and is saturation an issue? >>>> >>>> - aurf >>>> >>>> On Feb 4, 2014, at 8:27 PM, Graham Allan <allan@physics.umn.edu> wrote: >>>> >>>>> This may well be a question with no real answer but since we're >>>>> speccing >>>>> out a new ZFS-based storage system, I've been asked what the maximum >>>>> number >>>>> of drives it can support would be (for a hypothetical expansion >>>>> option). >>>>> While there are some obvious limits such as SAS addressing, I assume >>>>> there >>>>> must be more fundamental ones in the kernel or drivers, and the >>>>> practical >>>>> limits will be very different from the hypothetical ones. >>>>> >>>>> So far the largest system we've built is using three 45-drive chassis >>>>> on >>>>> one SAS2008 (mps) controller, so 135 drives total. Over many months of >>>>> running we had several drives fail and be replaced, and eventually the >>>>> OS >>>>> (9.1) failed to assign new da devices. It was time to patch the system >>>>> and >>>>> reboot anyway, which solved it, but we did wonder if we were running >>>>> into >>>>> some kind of limit around 150 drives - though I don't see why. >>>>> >>>>> Interestingly we initially built this system with each drive chassis on >>>>> its own SAS2008 HBA, but it ultimately behaved better daisy-chained >>>>> with >>>>> only one. I think I saw a hint somewhere this could be to do with >>>>> interrupt >>>>> sharing... >>>>> >>>>> Thanks for any insights, >>>>> >>>>> Graham >>>>> _______________________________________________ >>>>> freebsd-fs@freebsd.org mailing list >>>>> http://lists.freebsd.org/mailman/listinfo/freebsd-fs >>>>> To unsubscribe, send any mail to "freebsd-fs-unsubscribe@freebsd.org" >>>> >>>> _______________________________________________ >>>> freebsd-fs@freebsd.org mailing list >>>> http://lists.freebsd.org/mailman/listinfo/freebsd-fs >>>> To unsubscribe, send any mail to "freebsd-fs-unsubscribe@freebsd.org" >>> >>> >>> >>> _______________________________________________ >>> freebsd-fs@freebsd.org mailing list >>> http://lists.freebsd.org/mailman/listinfo/freebsd-fs >>> To unsubscribe, send any mail to "freebsd-fs-unsubscribe@freebsd.org" > >
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?CAOeNLuohed9PB7SXNvB40N9-8Cna6DOg0mF5vXn48%2B0rTF3Dog>