Date: Wed, 03 Mar 2010 22:08:05 +0100 From: Attila Nagy <bra@fsn.hu> To: Alexander Motin <mav@FreeBSD.org> Cc: svn-src-head@freebsd.org, svn-src-all@freebsd.org, src-committers@freebsd.org Subject: Re: svn commit: r204648 - head/sys/dev/ciss Message-ID: <4B8ECFB5.3040902@fsn.hu> In-Reply-To: <4B8EC9E0.6050703@FreeBSD.org> References: <201003031758.o23HwfnD023194@svn.freebsd.org> <4B8EC54E.4050705@fsn.hu> <4B8EC9E0.6050703@FreeBSD.org>
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Alexander Motin wrote: > Attila Nagy wrote: > >> Alexander Motin wrote: >> >>> Author: mav >>> Date: Wed Mar 3 17:58:41 2010 >>> New Revision: 204648 >>> URL: http://svn.freebsd.org/changeset/base/204648 >>> >>> Log: >>> Several changes to fix livelock under high load, introduced by r203489: >>> - change the way in which command queue overflow is handled; >>> - do not expose to CAM two command slots, used for driver's internal purposes; >>> - allow driver to use up to 1024 command slots, instead of 256 before. >>> >>> >> Thank you for hunting this bug down. Do you plan to increase the maximum >> logical device limit as well? >> > > Not sure. I just have no idea why this limitation was enforced. Even if > I personally don't see problems from increasing it, it would be nice if > somebody more aware of this driver tell whether it is correct for all > supported hardware. I just don't have any. Thank you for provided > access. If nobody responds, we may try our luck in CURRENT. > >From the VCS history it seems this limit is there from the very first revision, which was made for the Compaq SmartRAID 5* line. Those were parallel SCSI controllers, so 15 was a sane value there (you couldn't attach more than 15 devices to the bus). The change came with the new SAS controllers, which can have external connectors, so a lot of drives (and logical drives) can be attached to them. I use SAS (P800) controllers with increased limit without any ill effects, but can try older ones (SCSI: 5i, 6i) too if needed.
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