Method and apparatus for efficient memory replication for high availability (HA) protection of a virtual machine (VM)
First Claim
1. A method for providing high availability (HA) protection to a virtual machine (VM) executing on an active host, the method comprising:
- at a checkpoint interval time, a first processor of an active host executing a copy thread;
the copy thread copying a dirty memory page into a ring buffer;
after the copy thread has copied the dirty memory page into the ring buffer, the first processor of the active host executing a send thread; and
the send thread sending the dirty memory page in the ring buffer 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, the first processor synchronizing 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, a second processor enabling a dynamic disk barrier process to be applied at a later checkpoint time interval; and
at a checkpoint interval time after the later checkpoint time interval, the first processor and the second processor synchronizing 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.
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Abstract
High availability (HA) protection is provided for an executing virtual machine. At a checkpoint in the HA process, the active server suspends the virtual machine; and the active server copies dirty memory pages to a buffer. During the suspension of the virtual machine on the active host server, dirty memory pages are copied to a ring buffer. A copy process copies the dirty pages to a first location in the buffer. At a predetermined benchmark or threshold, a transmission process can begin. The transmission process can read data out of the buffer at a second location to send to the standby host. Both the copy and transmission processes can operate substantially simultaneously on the ring buffer. As such, the ring buffer cannot overflow because the transmission process continues to empty the ring buffer as the copy process continues. This arrangement allows for smaller buffers and prevents buffer overflows.
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Citations
19 Claims
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1. A method for providing high availability (HA) protection to a virtual machine (VM) executing on an active host, the method comprising:
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at a checkpoint interval time, a first processor of an active host executing a copy thread; the copy thread copying a dirty memory page into a ring buffer; after the copy thread has copied the dirty memory page into the ring buffer, the first processor of the active host executing a send thread; and the send thread sending the dirty memory page in the ring buffer 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, the first processor synchronizing 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, a second processor enabling a dynamic disk barrier process to be applied at a later checkpoint time interval; and at a checkpoint interval time after the later checkpoint time interval, the first processor and the second processor synchronizing 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. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. 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:
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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;
anat 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. - View Dependent Claims (12, 13, 14)
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15. 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. - View Dependent Claims (16, 17, 18, 19)
- an active host, the active host comprising;
Specification