I think direct iscsi access from guest VM probably is faster than virtual disk in XenServer,
in XenServer, virtual disk is emulated by dom0 application, virtual NIC is emulated by dom0 Kernel, direct iscsi access basically moves from virtual disk emulation to virtual NIC emulation. Anthony > -----Original Message----- > From: Alex Huang [mailto:alex.hu...@citrix.com] > Sent: Thursday, February 07, 2013 4:21 PM > To: Marcus Sorensen; Mike Tutkowski > Cc: Edison Su; cloudstack-dev@incubator.apache.org > Subject: RE: Supporting SolidFire QoS Before 4.2 > > > > > -----Original Message----- > > From: Marcus Sorensen [mailto:shadow...@gmail.com] > > Sent: Thursday, February 07, 2013 3:29 PM > > To: Mike Tutkowski > > Cc: Edison Su; cloudstack-dev@incubator.apache.org > > Subject: Re: Supporting SolidFire QoS Before 4.2 > > > > He's saying that the VM can connect via iscsi directly to the > > solidfire device, rather than the host. You'd lose more performance > > that way and there's more overhead, but it would be a way to give > > individual VMs their own solidfire LUN. > > > Marcus, > > I'm interested in your comment here. Why do you think vm having direct > iscsi access actually lose performance? I would think it's actually > faster because there's nothing translating the raw LUN into a raw disk. > > --Alex
