Re: [sheepdog] Qemu Live Migration and Cache
Am 2012-06-07 12:07, schrieb Yibin Shen: On Thu, Jun 7, 2012 at 5:38 PM, Liu Yuan namei.u...@gmail.com wrote: Maybe you refer to object cache? Yes, sorry, mixed that two... Without object cache, the answer is NO, the data will be known to the cluster as soon as the request is completely. With object cache enabled, probably 'nope' again, but I am not 100% sure, live migration mechanism from QEMU will issue a flush request to sheep and block for it, then will migrate memory to other machine. For the last try with live migration, it did the right thing for me, but you'd better test it with your own. When I have time, I'll try it again and give you a solid answer.so qemu will call sync operation before live migration,(nearly) all dirty objects will be flushed to sheepdog cluster. Thanks for your infos. I am using libvirt with virt-manager on top to manage my virtual machines. With sheepdog 0.2.4 live migration works without problems for month. If the current sheepdog version will work for me, I make some more migration tests and give a feedback. Cheers Bastian -- sheepdog mailing list sheepdog@lists.wpkg.org http://lists.wpkg.org/mailman/listinfo/sheepdog
[sheepdog] Qemu Live Migration and Cache
I have a question about migration a Qemu Virtual Machines from one node to another... Is there something I have to pay attention when using the farm cache mechanisms? For example, is it possible, that I ran my virtual Machine V on host A, Start a live migration to host B, but some content in the cache from host A would not known to the rest of the cluster in time? Cheers Bastian -- sheepdog mailing list sheepdog@lists.wpkg.org http://lists.wpkg.org/mailman/listinfo/sheepdog
Re: [sheepdog] Qemu Live Migration and Cache
On 06/07/2012 05:19 PM, Bastian Scholz wrote: I have a question about migration a Qemu Virtual Machines from one node to another... Is there something I have to pay attention when using the farm cache mechanisms? Farm doesn't cache any data for regular IO. Instead, Farm caches snapshot objects for recovery, which is totally irreverent to data consistency of running VM. Maybe you refer to object cache? For example, is it possible, that I ran my virtual Machine V on host A, Start a live migration to host B, but some content in the cache from host A would not known to the rest of the cluster in time? Without object cache, the answer is NO, the data will be known to the cluster as soon as the request is completely. With object cache enabled, probably 'nope' again, but I am not 100% sure, live migration mechanism from QEMU will issue a flush request to sheep and block for it, then will migrate memory to other machine. For the last try with live migration, it did the right thing for me, but you'd better test it with your own. When I have time, I'll try it again and give you a solid answer.so Thanks, Yuan -- sheepdog mailing list sheepdog@lists.wpkg.org http://lists.wpkg.org/mailman/listinfo/sheepdog
