Re: [Qemu-devel] [PATCH] This patch adds a new block driver : iSCSI

[Dor Laor]

On 09/15/2011 09:04 AM, Paolo Bonzini wrote:
> On 09/15/2011 01:08 AM, ronnie sahlberg wrote:
> > I think it is reasonable to just not support iscsi at all for
> > blocksize that is not multiple of 512 bytes
> > since a read-modify-write cycle across a network would probably be
> > prohibitively expensive.
>
> Agreed.
>
> > .bdrv_flush() I can easily add a synchronous implementation of this
> > unless your patch is expected to be merged
> > in the near future.
>
> We need the same patch for NBD, so I wouldn't bother with the
> synchronous flush.
>
> Paolo

It seems to me that using a qemu external initiator/target pairs like 
Orit's original design in 
http://wiki.qemu.org/Features/LiveBlockMigration#ISCSI_for_non_shared_storage 
would be a simpler (in terms of qemu code..) and flexible solution.

I agree that embedding the iscsi initiation in qemu can simplify the end 
user life but since this scenario is expected to be used by higher level 
software it's not relevant here. The risk is to have to maintain more 
code that won't be as general as the tgtd/lio solutions out there.