Date: Tue, 8 Feb 2005 15:49:56 -0600 From: Dan Nelson <dnelson@allantgroup.com> To: Scott Long <scottl@freebsd.org> Cc: freebsd-scsi@freebsd.org Subject: Re: how CAM/HBA probe for devices? Message-ID: <20050208214956.GA3104@dan.emsphone.com> In-Reply-To: <4208F618.3000400@freebsd.org> References: <E1CyYUO-0003tg-IT@cs1.cs.huji.ac.il> <4208F618.3000400@freebsd.org>
next in thread | previous in thread | raw e-mail | index | archive | help
In the last episode (Feb 08), Scott Long said: > For iSCSI, this obviously won't work. CAM has no concept of iSCSI > addresses, and even if it did, doing a linear scan of even a small > subnet would be prohibitively expensive. What is really needed is a > new XPT layer that understands iSCSI. By this, I mean a layer that > understands how to properly scan and detect targets, how to log into > them, etc. It should also have a certain amount of flexibility so > that hardware-assisted solutions can plug in and pick-and-choose the > pieces they need from the transport layer. > > Lucent did an iSCSI initiator for FreeBSD 4.x a while back and I > think they got around all of this by telling CAM not to auto-scan at > boot, followed by having the driver announce devices to CAM directly > (look at the ATAPI-CAM code for an example of how to do this) and do > all the detection and login work behind CAM's back. This really > should only be considered a hack though. If you're interested, I > might be able to dig up the link to it. We never pursued integrating > it to the FreeBSD tree because of very restrictive licensing terms on > it. The fibre-channel drivers (isp,mpt) must have been the first to have hit this problem; do they do the same thing as atapicam? -- Dan Nelson dnelson@allantgroup.com
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?20050208214956.GA3104>