On Fri, Oct 23, 2009 at 8:10 PM, Alexander Graf <agraf@xxxxxxx> wrote: > > On 23.10.2009, at 12:41, MORITA Kazutaka wrote: > > On Fri, Oct 23, 2009 at 12:30 AM, Avi Kivity <avi@xxxxxxxxxx> wrote: > > How is load balancing implemented? Can you move an image transparently > > while a guest is running? Will an image be moved closer to its guest? > > Sheepdog uses consistent hashing to decide where objects store; I/O > load is balanced across the nodes. When a new node is added or the > existing node is removed, the hash table changes and the data > automatically and transparently are moved over nodes. > > We plan to implement a mechanism to distribute the data not randomly > but intelligently; we could use machine load, the locations of VMs, etc. > > What exactly does balanced mean? Can it cope with individual nodes having > more disk space than others? I mean objects are uniformly distributed over the nodes by the hash function. Distribution using free disk space information is one of TODOs. > Do you support multiple guests accessing the same image? > > A VM image can be attached to any VMs but one VM at a time; multiple > running VMs cannot access to the same VM image. > > What about read-only access? Imagine you'd have 5 kvm instances each > accessing it using -snapshot. By creating new clone images from existing snapshot image, you can do the similar thing. Sheepdog can create cloning image instantly. -- MORITA, Kazutaka NTT Cyber Space Labs OSS Computing Project Kernel Group E-mail: morita.kazutaka@xxxxxxxxxxxxx -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
