Date: Thu, 09 Mar 2006 15:15:22 -0600 From: Eric Anderson <anderson@centtech.com> To: Nate Lawson <nate@root.org> Cc: freebsd-scsi@freebsd.org Subject: Re: scsi-target and the buffer cache Message-ID: <44109AEA.5030209@centtech.com> In-Reply-To: <44105A01.5080309@root.org> References: <4395BF04.50101@centtech.com> <43960F55.3010508@root.org> <43975926.1010302@centtech.com> <43975F5F.5080901@samsco.org> <439782AA.6000408@root.org> <4397B731.6010308@centtech.com> <4397B82C.5020004@samsco.org> <4397EBC7.9030105@root.org> <440F5141.7010002@centtech.com> <44105A01.5080309@root.org>
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Nate Lawson wrote: > [mailing list changed to scsi@] > > Eric Anderson wrote: >> Nate Lawson wrote: >>> Scott Long wrote: >>>> Eric Anderson wrote: >>>> >>>>> Nate Lawson wrote: >>>>>> Agree 100%. While having it in usermode means there are boundary >>>>>> crossings that increase per-transaction latency, the actual bulk >>>>>> data transfer is via zero-copy IO and you should be able to >>>>>> exceed the data transfer rates of several 10K RPM drives on >>>>>> decent hardware. >>>>> >>>>> Ok, great.. Now, will scsi_target work ok with raw devices, or >>>>> only files? (although I'm not sure theres all that much >>>>> difference really). >>>>> >>>> >>>> You can write your userland code to use whatever files or devices you >>>> want. Are you talking about the scs_target.c code in >>>> /usr/share/examples? That's just a skeletal example that you can use >>>> as a starting point for your own work. >>> >>> No, it's not just a skeletal example. You can point it at a raw >>> device as the backing store file and it will work as a block device >>> (i.e. RBC command set). It has been tested as working at least >>> moderately fast over SCSI, FC, and firewire. >>> >> >> I'm finally getting around to playing with this, and I'm having some >> problems. First, I can't seem to make one isp card in target mode >> and the other an initiator. I've messed with adding the following to >> loader.conf: >> >> hint.isp.0.role="initiator" >> hint.isp.1.role="target" >> >> that still doesn't show my currently connected fiber channel devices >> on the initiator side. >> >> I've tried a few different kernel options, currently I have: >> >> options ISP_TARGET_MODE=1 >> device targ >> >> I've also tried just: >> >> options ISP_TARGET_MODE >> >> and that doesn't seem to allow me to select one either. > > hints aren't needed. Here's an intro on how to use it: > http://root.org/~nate/freebsd/scsi/README.targ > > The same card is in target or initiator mode based on the scsi_target > user program. When it's running, target mode is enabled. Hmm. Then shouldn't a camcontrol rescan all camcontrol devlist -v show me all the devices on the FC network? If I remove the target mode stuff out, and do that, I see all my devices. With it in, I see no devices. When I run the scsi_target tool (scsi_target -d 0:3:0 /mnt/testfile), it shows a bunch of "sending ccb (0x332)" and (0x334) messages alternating for a couple hundred lines, then "main loop beginning" and a few other messages. If you want the full details, I'd be glad to sent them. Once scsi_target is running, my other FC initiator (FreeBSD 6.1- also) can see it. > >> Anyhow, I've compiled scsi_target (from >> /usr/share/examples/scsi_target), and tried to run it using a 20gb >> file as the target, and still I can't seem to get it working. >> Is there a doc somewhere I need to read? >> >> Also - as a side note, the Makefile for scsi_target seems like it's >> missing a path variable in order to do a make install, but that's not >> a real issue. > > There was some debate when I imported it whether to make it an example > or usr.sbin. Given the lack of updates (i.e. ki_sig or whatever), I > probably should have put it somewhere else. Is it a totally non-supported kind of tool? Is there another option for scsi target mode? Thanks! Eric -- ------------------------------------------------------------------------ Eric Anderson Sr. Systems Administrator Centaur Technology Anything that works is better than anything that doesn't. ------------------------------------------------------------------------
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