Re: NetBSD iSCSI target on ZVOL used as block device for Qemu - iSCSI: NOP timeout

[mlelstv%serpens.de@localhost (Michael van Elst)]

mp%petermann-it.de@localhost (Matthias Petermann) writes:

>Just out of interest - how can the state of the iscsi implementation in 
>NetBSD-Base be assessed in general? Is the implementation outdated 
>and/or unstable, or are there (compatibility?) reasons for this? 

There is a userland implementation (iscsi-target / iscsi-initiator)
that is basically the reference (or maybe example) code plus some
integration as userland filesystem.

The code lacks features and isn't compatible with other iscsi
implementations. It's stable but there is no development.


Then there is a the kernel iscsi initiator (iscsctl / iscsid).
It's more compatible, much faster, but probably still a little buggy.
Most bugs and fixes in the last years came from me.

I use the kernel iscsi initiator together with istgt or the Linux
iSCSI target.



>According to the description, isgt is the same as the FreeBSD iscsi 
>implementation. As far as I can tell, both target implementations run in 
>user space, i.e. operate on the same logical level, and neither can 
>claim any advantages, e.g. running directly in kernel space and thus 
>saving context switches.

There is no real reason to run the target in the kernel.



>Of course, I realise that there are more 
>important issues and that such a complex protocol does not port itself. 
>But would it be a far-future option to adopt the istgt implementation in 
>NetBSD-base?

Would probably be a good thing to drop the reference code and to adopt
istgt.