Hello all, Sheepdog is a distributed storage system that QEMU VM and RESTful services (in progress).
Erasure coding is now seamlessly functional with all other features such as snapshot/clone/cluster-wide/multi-disk/auto-healing e.c with following characteristics: 1 Data is erasure coded automatically while being written to sheepdog storage, no extra operations. 2 Support random read/write, in-place-update, misaligned read/write 3 Support to run any type VM images or attach as a vdisk of a VM 4 User-defined coding scheme on a VDI basis 5 Better read/write performance compared to fully replication scheme 6 A single cluster can both support replicated VDI or erasure-coded VDI You can get more info at https://github.com/sheepdog/sheepdog/wiki for a general wiki https://github.com/sheepdog/sheepdog/wiki/Erasure-Code-Support for erasure coding Anyone who is interested can git clone https://github.com/sheepdog/sheepdog.git For a 10 minutes quick start with a single machine, you can try: (Assume you are debian based system) # Compile from the source $ sudo apt-get install liburcu-dev $ git clone git://github.com/sheepdog/sheepdog.git $ cd sheepdog $ ./autogen.sh; ./configure --disable-corosync $ make; sudo make install # Create a 6 node cluster with local driver $ for i in `seq 0 5`; do sheep /tmp/store$i -n -c local -z $i -p 700$i;done $ dog cluster format # Create a replicated thin-provisioned 20G volume with 3 copies $ dog vdi create -c 3 replica 20G $ dog vdi list # show vdi list $ dog node info # show node information $ dog cluster info # show cluster infomation # Create a erasure-coded (4 data strips and 2 parity strips) 20G volume $ dog vdi create -c 4:2 erasure 20G # Now you should have 2 vdi created $ dog vdi list # You can install OS on these volumes with upstream QEMU $ qemu-system-x86_64 -m 1024 --enable-kvm \ -drive file=sheepdog:erasure,if=virtio -cdrom path_to_your_iso # or attach the volumes with existant VM $ qemu-system-x86_64 -m 1024 --enable-kvm \ -drive file=your_image,if=virtio -drive file=sheepdog:erasure,if=virtio # Take a live disk-only snapshot of running VM $ dog vdi snapshot -s tag erasure # Mount the volume(vdi) to local storage file system $ sheepfs dir $ echo erasure > dir/vdi/mount # then you can do whatever with the mounted file at dir/vdi/volume/erasure Have fun And feedbacks are always welcome. Thanks Yuan