[sheepdog] Sheepdog 0.6.0 released

[MORITA Kazutaka]

Hi all,

I'm pleased to announce the availability of the 0.6.0 release.
The software is available from GitHub:
https://github.com/collie/sheepdog/archive/v0.6.0.tar.gz

Major features since 0.5.6 include:

 - Add MD support

   Sheepdog can manage multiple disks with one daemon now.  The basic
   idea of MD is RAID-0 like mechanism that distributes sheep objects
   on the local disks without parity or replicating, which instead
   relies on the sheepdog's replicated storage to recover the lost
   objects on the faulty disk.

 - Add journaling support

   Yuan reworked the old journal implementation and boosted random
   write performance of sheep.

 - Move farm from sheep to collie

   The farm cluster snapshot in sheep had some drawbacks:

     1. After a new node joins the cluster, all former snapshots are
        not available to be restored.
     2. It is hard to backup cluster snapshot to another storage
        system for disaster-tolerance.
     3. It is hard to initialize a new cluster by loading another
        cluster's snapshot.

   New implementation is to move "farm" from sheep to collie and save
   cluster snapshot to a local path.  This retains all features from
   "farm", including:

     1. object de-duplication
     2. incremental store capability

   In addition, it also provides ability of:

     1. export cluster snapshot to other storage device for backup and
        disaster-tolerance
     2. deploy new cluster by restore from one snapshot of other
        cluster

 - Use hash check for vdi check and recovery

   To reduce network traffic, Sheepdog uses a hash values to compare
   objects between local and remote.

 - Shepherd

   Currently, corosync doesn't have enough scalability and ZooKeeper
   is not stable under heavy network traffic.  This is an initial
   implementation for yet another cluster coordinator to solve the
   problem.

   Shepherd is not mature yet.  Don't use it for other than testing
   purposes.

 - Add support for a trim command

   With this support, Sheepdog can remove the objects which are
   unnecessary for the guest virtual machines.


The next release 0.7.0 will be in the end of August.  We decided to
use the same release cycle as QEMU.  I'll announce our schedule after
QEMU community announce theirs.

Thanks,

Kazutaka