[Stgt-devel] User-mode iSER

[Tom Tucker]

On Wed, 2006-08-02 at 07:21 +0900, FUJITA Tomonori wrote:
[...snip...]
> > 
> > Also, won't a user-mode approach support virtual target devices more
> > easily? 
> 
> There's no difference. Note that we try to push a small portion of the
> iSCSI tcp driver into kernel (iSCSI protocol processing). Both
> approaches perform SCSI protocol processing, I/O in user space.
> I think that you can easily implement any kind of vitalization, device
> vitalization (like virtual tape library) and backing vitalization
> (snapshot, encryption, compression, etc) in user space with both
> approaches.

Yes, I think this is true, in the current design, the target device I/O
is done in user space, so adding a new device type to trunk/usr is just
as easy. The event that initiates this I/O though comes from the kernel
over a netlink socket. Moving this all to user-space "might" make this
perform better and simplify the architecture.  

Do you think this is true or does it create as many problems as it
solves?

>