Re: iscsifs

[Stephen Borrill <netbsd%precedence.co.uk@localhost>]

On Wed, 25 Aug 2010, Brook Milligan wrote:
> Stephen Borrill writes:
> > >     amd64# iscsifs -v -h 127.0.0.1 -u nobody /mnt
> > >     [no response of any kind on the terminal]
> >
> > Correct operation is "no response of any kind on the terminal" - iscsifs
> > does not detach from the terminal. On another terminal type mount to see
> > what, if anything, has actually happened.
>
> This was the point I was missing.  Thanks.  By the way, would it not
> be useful to have some command line option that allowed iscsifs to go
> into the background?

Yes, it would. And going onto your later question about rc.d scripts, it 
would make that job easier. I've got a stack of changes to submit to 
iscsi-initiator (new name for iscsifs), so I'll add that to the list.

> When I run iscsifs on the amd64/5.0.2 machine, I do in fact see stuff
> under /mnt on another terminal.  Thus, something changed between 5.0
> and 5.0.2 to make this work and 5.2 may not be required.

5.1 is still recommended though.

>     # mount
>     /dev/puffs on /mnt type puffs|refuse:mnt (nosuid, nodev)
>     [ ... other stuff deleted ... ]
>
>     # ls -lR /mnt
>     total 64
>     drwxr-xr-x  2 root  wheel  512 Aug  2 09:06 127.0.0.1
>
>     /mnt/127.0.0.1:
>     total 64
>     drwxr-xr-x  2 root  wheel  512 Aug  2 09:06 target0
>
>     /mnt/127.0.0.1/target0:
>     total 448
>     lrw-r--r--  1 root  wheel          9 Aug  2 09:06 hostname -> 127.0.0.1
>     lrw-r--r--  1 root  wheel          9 Aug  2 09:06 ip -> 127.0.0.1
>     lrw-r--r--  1 root  wheel         16 Aug  2 09:06 product -> NetBSD iSCSI
>     -rw-r--r--  1 root  wheel  104857600 Aug  2 09:06 storage
>     lrw-r--r--  1 root  wheel         43 Aug  2 09:06 targetname -> 
> iqn.1994-04.org.netbsd.iscsi-target:target0
>     lrw-r--r--  1 root  wheel          8 Aug  2 09:06 vendor -> NetBSD
>     lrw-r--r--  1 root  wheel          4 Aug  2 09:06 version -> 0
>
> Interestingly, if I use "-h localhost" in the iscsifs command it
> fails, although other hostnames work fine and localhost is resolved by
> the nameserver.

I bet this is because it's resolving to ::1 (IPv6), but the target isn't 
bound to that.

> Now, I'm guessing that the current way to mount iscsifs as something
> useful is to write up a script to run during the boot process that
> will:
>
> - run iscsifs in the background
> - run vnconfig on the exposed storage
> - mount /dev/vnd?a somewhere
>
> and do the reverse on shutdown.
>
> Are there any such scripts out there that are trying to do this using
> the facilities of rc.subr so that they can be used within /etc/rc.d?

I'm not aware of any yet. But, as above, changes could be made to the 
initiator to make this task easier.

There are a couple of problems with the vnd approach. If the target dies, 
then it leaves the initiator side in a horrible mess. The initiator 
doesn't attempt reconnection, the vnd is still configured but backed by 
nothing. When this happens it can be impossible to cleanly shut the 
machine down.

iscsifs does have the option to generate device files, but to be of any 
use there is no point in just creating one - we really need both 
character and block device nodes to be created as well as nodes for the 
disklabel slices on the device.

--
Stephen