[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] XEN migration architecture question
Hi Eric, Migration will handle network interfaces and *network attached* block devices, even under i/o load. For network devices, an ARP advertisement is sent indicating the new location of the VM. We've tested this a fair bit in cluster environments and are able to migrate heavily i/o loaded servers very fast. You may see a few dropped packets, but TCP will take care of that. Block devices will see the backend disconnect when they are suspended, and should reconnect and reissue any outstanding requests when they resume. In our migration tests, we generally use network storage. One approach that seems to work pretty well is to import GNBD mounts in domain 0 and export them to the migrating domains -- /dev/gnbd/my-dom-disk will have relevance on both ends of the migration. Migration does not currently have explicit support for local block devices. It is possible to do, for instance using the block tap to tunnel the request stream over TCP between the two hosts, it just isn't clear that it's all that useful -- most people seem to want to use migration to offload a running VM completely. hth, andy. On Thu, 20 Jan 2005 12:44:40 -0800 (PST), Eric Tessler <maiden1134@xxxxxxxxx> wrote: > I have an important question about XEN's migation operation related to the > XEN block and network back/front drivers. If I migrate a domain from one > machine to another in the middle of heavy disk/network activity, what > happnens to the back/front end XEN drivers? (I see they have suspend/resume > operations but I don't believe they are being used) I see that the front > end drivers are passing machine addresses to the back-end drivers - are > these pointers somehow still valid when a domain is moved to another > machine? Shouldn't the drivers wait until there is no I/O activity before > being migrated? > > Thanks, > Eric > > ________________________________ > Do you Yahoo!? > Yahoo! Search presents - Jib Jab's 'Second Term' > > ------------------------------------------------------- This SF.Net email is sponsored by: IntelliVIEW -- Interactive Reporting Tool for open source databases. Create drag-&-drop reports. Save time by over 75%! Publish reports on the web. Export to DOC, XLS, RTF, etc. Download a FREE copy at http://www.intelliview.com/go/osdn_nl _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.sourceforge.net/lists/listinfo/xen-devel
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