At Sun, 09 Oct 2011 14:27:41 +0800, Liu Yuan wrote: > On 10/09/2011 02:21 PM, Yibin Shen wrote: > > > > > > On Sun, Oct 9, 2011 at 1:33 PM, Liu Yuan <namei.unix at gmail.com > > <mailto:namei.unix at gmail.com>> wrote: > > > > On 10/09/2011 01:07 PM, MORITA Kazutaka wrote: > > > > At Sun, 9 Oct 2011 11:21:52 +0800, > > Yibin Shen wrote: > > > > Use mmap is much simpler than local backup image, and without > > any influence to consistency. but it doesn't improve > > availability > > while whole sheepdog cluster is die(such as some odd network > > partition issue). > > > > anyway, if no one againsts, I will try to implement it in the > > near future (after we solved most stability issues) > > > > Can we implement it as an extension of the cache mechanism? > > If the > > local cache file has whole data in the Sheepdog VDI, we can > > regard it > > as a local backup image. > > > > Thanks, > > > > Kazutaka > > > > > > Maybe we can read-ahead in the whole data if network is not busy > > gradually? When the whole image is read in, we can mark it as > > 'complete'. If some time the cluster crashes, the complete image > > would help the VMs on the very node to survive the crash. The > > dirty bits will be flushed into cluster store in recovery stage. > > > > read-ahead whole image into memory? > > > > Into file in the local disk, that is supposed to be mmapped into qemu > process memory. Is it better to mmap in the gateway sheep daemon (usually, it is a local sheep daemon)? I think someone want to use Sheepdog from other than QEMU (e.g. iSCSI target). In addition, we can much more freely modified Sheepdog server codes than QEMU client ones. Thanks, Kazutaka |