Host Based Replication (HBR) was announced at VMworld 2010 “BC8432 SRM Futures: Host Based Replication” as a future, stuff but nearly production ready, mind feature of the next version release of Site Recovery Manager (SRM). Impressions are that this will not be an additionally licensed feature but will be a native feature of SRM. HBR will be a user selectable object of a virtual machine that allows the elimination of SAN array based replication while enabling protection of the VM. VMware will be implementing technology for native replication between SRM sites for performing full and incremental copies of virtual machine disk objects. Initial configuration of HBR will require a full sync of the vm with subsequent delta copies based on user selectable RPO values between 15 minutes and 24 hours.
Following are some of the highlights I recall:
- HBR will create (or require?) one or more Protection Groups
- Protected vms can not be mixed with Protection Groups with array based replication
- The technology monitoring the deltas of a protected vm is not CBT but something like it
- Replication is asynchronous, here time based and user definable
- No WAN compression
- No snapshot/journaling feature
- Possibly supports replication to/from local datastore
- Consistency with vm disks
- No option for consistency across multiple vm
- No support for RDM (very logical)
I see this feature as being huge for the SMB market as the array based replication is unarguably one of the larger costs of a traditional SRM. I see use case even for larger deployments and full intend to alter my environment for some lower priority virtual machines. For me this will free up licensed capacity on RecoverPoint, minimize disk space used for journaling and allow me to increase the RPO. This all sounds perfect for non top tier, static content application servers or largely read only file servers!
Speculation is that the Beta will be out late 2010 and that the new version of SRM will go GA near the middle of next year. Keyword there is speculation, this might have been from VMware employees but is not authoritative.