On Mon, Feb 23, 2009 at 09:41:20PM -0500, Dave Allan wrote: > Guido Günther wrote: >> On Mon, Feb 23, 2009 at 07:53:07PM +0000, Daniel P. Berrange wrote: >>> On Mon, Feb 23, 2009 at 06:03:07PM +0100, Guido G?nther wrote: >>>> On Fri, Feb 20, 2009 at 05:14:54PM -0500, David Allan wrote: >>>>> This patch contains the implementation Daniel Berrange did of storage >>>>> pools using SCSI HBAs. I have updated it for the current tree in >>>>> preparation for implementing NPIV support. Let me know what you >>>>> think. >>>> This looks like a great addition but I wonder if it is of any real use >>>> without supporting multipath? On SANs issuing I/O to some paths might >>>> cause severe performance penalties or the LUN might be visible but I/O >>>> is rejected until an explicit switch over command is sent. This would be >>>> handled transparently if multipath would be used on top. >>> This is *not* just for FibreChannel based HBAs. Even single host SATA >> Sure. >>> controllers show up as SCSI HBAs, so its perfectly usable even in that >>> case. So there's no need to block on multipath support >> It's just that using it on fibre based HBAs could cause trouble so >> thought I'd ask. > > Hi Guido, > > People can already use fibre channel block devices like any other block > devices with libvirt, so it's already possible for people to try to use > a passive path on an active/passive array, or use two active paths to > the same LU thinking they're different LUs, etc. That's being the case, > I don't think there's anything in this patch that makes it more likely > that people will make those kinds of mistakes. This patch just makes it > easy to list the LUs accessible by a particular host and provides a > foundation on which NPIV operations can be implemented. You are of course right. My mail probably sounded overly "pessimistic". Dan's SCSI HBA pool code is a great addition! I just can't wait until we support active/passive arrays ;) -- Guido -- Libvir-list mailing list Libvir-list@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/libvir-list