Abstract: A software component is executed to carry out a task, the task including a subtask. An external function is called to perform the subtask, the external function executing in a separate thread or process. The component receives an observation recorded by the external function, the observation including an identifier of a possible error condition and instance data associated with the possible error condition. The possible error condition being a cause of the failure of the external function to carry out the subtask. If the task cannot be completed, then a new observation is recorded along with the received observation, the new observation being related to a possible error condition of the component, which is a cause of the failure of the component to carry out the task. When the task can be completed despite the failure of the external function, the observation recorded by the external function is cleared.

Abstract: A method for migrating a virtual machine disk (VM disk) from first physical storage to second physical storage while the virtual machine (VM) is running, the method comprising: (a) taking a snapshot of the VM disk as represented by a first parent VM disk stored on the first physical storage, whereby a first child VM disk is created on one of the first or second physical storage; (b) copying the first parent VM disk to the second physical storage as a second parent VM disk; (c) re-parenting the first VM child disk to the second parent VM disk; and (d) consolidating the first child VM disk and the second parent VM disk.

Abstract: A swap space is provided for a host computer system, where the swap space includes a plurality of swap files with each individual swap file for swapping data only for a single corresponding virtual machine (VM). The per-VM swap space is used solely by the single, corresponding VM, such that only that particular VM's memory is allowed to be swapped out to the swap file.

Abstract: A software component is executed to carry out a task, the task including a subtask. An external function is called to perform the subtask, the external function executing in a separate thread or process. The component receives an observation recorded by the external function, the observation including an identifier of a possible error condition and instance data associated with the possible error condition. The possible error condition being a cause of the failure of the external function to carry out the subtask. If the task cannot be completed, then a new observation is recorded along with the received observation, the new observation being related to a possible error condition of the component, which is a cause of the failure of the component to carry out the task. When the task can be completed despite the failure of the external function, the observation recorded by the external function is cleared.

Abstract: A system for increasing the efficiency of migrating, at least in part, a virtual machine from a source host to a destination host is described wherein the content of one or more portions of the address space of the virtual machine are each uniquely associated at the source host with a signature that may collide, absent disambiguation, with different content at the destination host. Code in both the source and destination hosts disambiguates the signature(s) so that each disambiguated signature may be uniquely associated with content at the destination host, and so that collisions with different content are avoided at the destination host. Logic is configured to determine whether the content uniquely associated with a disambiguated signature at the destination host is already present in the destination host memory, and, if so, to back one or more portions of the address space of the virtual machine having this content with one or more portions of the destination host memory already holding this content.

Abstract: A virtual machine is suspended and quickly restarted while maintaining the VM's state. The method is quick enough so that network connections are maintained across the restart and the guest operating system and guest applications running in the VM are not aware of the restart. As a result, users and clients connected to the VM do not notice any downtime or disruption to the VM. After suspension and before the restart, VM configuration changes that would not be possible or be very difficult through code changes alone while the VM was running can be made.

Abstract: Persistent data of virtual machines are migrated between and across data stores using a method that provides for a bounded disk size, low performance overhead, arbitrarily low downtimes, atomic switch-over, and ability to build optimizations based around block level heuristics. The method includes the steps of copying the persistent data at the source data store to the destination data store, updating a bitmap data structure during the copying step to indicate which blocks of the persistent data have been modified during the copying step, identifying the blocks that have been modified during the copying step using the bitmap data structure, and copying the identified blocks to the destination data store. The method may further include the step of determining that the number of the identified blocks is below a predetermined threshold and suspending the virtual machine prior to the second copying step.

Abstract: A swap space is provided for a host computer system, where the swap space includes a plurality of swap files with each individual swap file for swapping data only for a single corresponding virtual machine (VM). The per-VM swap space is used solely by the single, corresponding VM, such that only that particular VM's memory is allowed to be swapped out to the swap file.

Abstract: A swap space is provided for a host computer system, where the swap space includes a plurality of swap files with each individual swap file for swapping data only for a single corresponding virtual machine (VM). The per-VM swap space is used solely by the single, corresponding VM, such that only that particular VM's memory is allowed to be swapped out to the swap file.

Abstract: A method for migrating a virtual machine disk (VM disk) from first physical storage to second physical storage while the virtual machine (VM) is running, the method comprising: (a) taking a snapshot of the VM disk as represented by a first parent VM disk stored on the first physical storage, whereby a first child VM disk is created on one of the first or second physical storage; (b) copying the first parent VM disk to the second physical storage as a second parent VM disk; (c) re-parenting the first VM child disk to the second parent VM disk; and (d) consolidating the first child VM disk and the second parent VM disk.

Abstract: One embodiment is a method for tracking data correspondences in a computer system including a host hardware platform, virtualization software running on the host hardware platform, and a virtual machine running on the virtualization software, the method including: (a) monitoring one or more data movement operations of the computer system; and (b) storing information regarding the one or more data movement operations in a data correspondence structure, which information provides a correspondence between data before one of the one or more data movement operations and data after the one of the one or more data movement operations.