Method and apparatus for efficient memory replication for high availability (HA) protection of a virtual machine (VM)

A non-transitory computer readable medium having stored thereon instructions that cause a computing system to execute a method for providing high availability (HA) protection to a running virtual machine (VM) executing on an active host, the instructions comprising:

• instructions to determine if a checkpoint has arrived during an HA process;
• if a checkpoint has arrived, instructions to suspend operation of the VM;
• instructions to execute a copy thread that copies two or more dirty memory pages to a ring buffer at the active host;
• instructions to determine if a threshold has been reached in the ring buffer, wherein the threshold is associated with data availability in the ring buffer;
• instructions to determine if the copy thread has stopped executing;
• and
• if the threshold has been reached or the copy thread has stopped executing, instructions to execute a send thread that sends the two or more dirty memory ages to a standby host, wherein the copy thread and the send thread execute on the ring buffer simultaneously;
• after initially synchronizing a disk image of the VM by copying the disk image of the VM from a disk storage at the active host to the standby host and while maintaining the synchronization of the disk image of the VM, instructions to synchronize a memory image of the VM between the active host and the standby host, wherein, after memory synchronization, the memory image of the VM and the disk image of the VM are synchronized;
• once disk synchronization and memory synchronization are completed and the disk image and the memory image of the VM are synchronized, instructions to enable a dynamic disk barrier process to be applied at a later checkpoint time interval;
• an
• at a checkpoint interval time after the later checkpoint time interval, instructions to synchronize the disk image and the memory of the VM between the active host and the standby host for all changes, wherein the standby host controls a synchronization control process at the standby host that utilizes the dynamic disk barrier to keep the memory and the disk image of the VM synchronized at the checkpoint interval for the VM on the active host and the standby host.

A server computing system comprising:

• an active host, the active host comprising:
• a main memory operable to store a memory image associated with a virtual machine (VM);
• a ring buffer operable to store one or more dirty memory pages from the main memory;
• a first processor in communication with the main memory and the ring buffer, the first processor executing the VM, the first processor operable to execute a memory replication module, the memory replication module operable to:
• execute a copy thread that copies two or more dirty memory pages to the ring buffer;
• determine if a threshold has been reached in the ring buffer, wherein the threshold is associated with a portion of a capacity of the ring buffer;
• and
• if the threshold has been reached, instructions to execute a send thread that sends the two or more dirty memory ages to a standby host, wherein:
• the send thread chases the copy thread;
• the send thread and executes simultaneously as the copy thread;
• and
• the send thread executes on a different section of the ring buffer than the copy thread;
• after initially synchronizing a disk image of the VM by copying the disk image of the VM from a disk storage at the active host to the standby host and while maintaining the synchronization of the disk image of the VM, synchronize a memory image of the VM between the active host and the standby host, wherein, after memory synchronization, the memory image of the VM and disk image of the VM are synchronized;
• a second processor operable to:
• once disk synchronization and memory synchronization are completed and the disk image and the memory image of the VM are synchronized, enable a dynamic disk barrier process to be applied at a checkpoint time interval;
• and
• the first and second processors operable to:
• at a checkpoint interval time thereinafter, synchronize the disk image and the memory of the VM between the active host and the standby host for all changes, wherein the standby host controls a synchronization control process at the standby host that utilizes the dynamic disk barrier to keep the memory and disk image of the VM synchronized at the checkpoint interval for the VM on the active host and the standby host.