CAM Target Layer available

Kenneth D. Merry ken at
Thu Jan 5 14:24:36 UTC 2012

On Thu, Jan 05, 2012 at 01:03:57 -0800, Julian Elischer wrote:
> On 1/4/12 8:39 PM, Kenneth D. Merry wrote:
> >The CAM Target Layer (CTL) is now available for testing.  I am planning to
> >commit it to to head next week, barring any major objections.
> >
> >CTL is a disk and processor device emulation subsystem originally written
> >for Copan Systems under Linux starting in 2003.  It has been shipping in
> >Copan (now SGI) products since 2005.
> >
> >It was ported to FreeBSD in 2008, and thanks to an agreement between SGI
> >(who acquired Copan's assets in 2010) and Spectra Logic in 2010, CTL is
> >available under a BSD-style license.  The intent behind the agreement was
> >that Spectra would work to get CTL into the FreeBSD tree.
> [...]
> >  - Note that the ramdisk backend is a "fake" ramdisk.  That is, it is
> >    backed by a small amount of RAM that is used for all I/O requests.  
> >    This
> >    is useful for performance testing, but not for any data integrity 
> >    tests.
> so, If I read this correctly, I should be able to export a fusion-io 
> flash card with
> ctladm create -b block -o file=/dev/fio0  ??

Yes, that would work.

Although last time I tried using a block device, as opposed to a file, I
ran into a GEOM panic that looked like it should be pretty easy to fix.  If
you run into that, you can get around it by disabling sending sync cache to
the back end:

ctladm realsync off

> >  - To add a LUN with the block/file backend:
> >
> >	truncate -s +1T myfile
> >	ctladm create -b block -o file=myfile
> >	ctladm port -o on
> >

Kenneth Merry
ken at FreeBSD.ORG

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