Date: Thu, 09 Mar 2006 08:38:25 -0800 From: Nate Lawson <nate@root.org> To: Eric Anderson <anderson@centtech.com> Cc: freebsd-scsi@freebsd.org Subject: Re: scsi-target and the buffer cache Message-ID: <44105A01.5080309@root.org> In-Reply-To: <440F5141.7010002@centtech.com> 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>
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[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. > 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. -- Nate
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