Storage reservation pools for virtual infrastructure

A non-transitory, computer-readable storage medium encoded with instructions executable by a processor to allocate storage from a storage reservation pool to virtual disks of virtual machines, the instructions comprising:

• assigning a quota on available space from the storage reservation pool;
• adding the virtual disks to the storage reservation pool;
• for each virtual disk belonging to the storage reservation pool:
• allocating a first epoch specific storage space to the virtual disk based on the available space in the storage reservation pool, wherein the first epoch specific storage space corresponds to a first epoch of time, and the first epoch of time occurs prior to a second epoch of time;
• creating a memory map for the virtual disk to track space used by the virtual disk;
• for every write request to the virtual disk during the first epoch:
• updating the memory map with information about the write request, including a write location and an amount of data written;
• based on the memory map and without querying the storage reservation pool, determining if the used space consumed by the virtual disk is greater than a threshold of the first epoch specific storage space;
• and
• when the used space is greater than the threshold of the first epoch specific storage space:
• predicting additional space that will be consumed by other writes for the remainder of the first epoch to the virtual disk;
• determining if the additional space is available from the storage reservation pool;
• and
• when the additional space is available from the storage reservation pool:
• increasing the first epoch specific storage space by the additional space;
• and
• proceeding with the write request to the virtual disk.

A computer system, comprising:

• one or more host computers, each host computer running a hypervisor, the hypervisor running one or more virtual machines, each virtual machine having one or more virtual disks and one or more input/output (I/O) filters installed on the one or more virtual disks, respectively,
• a processor;
• a computer-readable medium encoded with instructions, when executable by the processor, causes the processor configured to:
• create a storage reservation pool from one or more datastores;
• for each virtual disk belonging to the storage reservation pool:
• assign a quota on available space from the storage reservation pool;
• add the virtual disk to the storage reservation pool;
• create an I/O filter for the virtual disk;
• allocate a first epoch specific storage space to the virtual disk based on the available space in the storage reservation pool, wherein the first epoch specific storage space corresponds to a first epoch of time, and the first epoch of time occurs prior to a second epoch of time;
• the I/O filter is configured to create a memory map for the virtual disk to track space used by the virtual disk;
• each time the I/O filter receives a write request to the virtual disk during the first epoch:
• the I/O filter is configured to update the memory map, including recording a write location and an amount of the write data in the memory map;
• based on the memory map and without querying the storage reservation pool, the I/O filter is configured to determine if the used space consumed by the virtual disk is greater than a threshold of the first epoch specific storage space;
• and
• when the I/O filter determines the used space is greater than the threshold of the first epoch specific storage space:
• the I/O filter is configured to predict additional space that will be consumed by other writes for the remainder of the first epoch to the virtual disk;
• the I/O filter is configured to request the additional space;
• the processor is configured to determine if the additional space is available from the storage reservation pool;
• and
• when the processor determines the additional space is available from the storage reservation pool:
• the processor is configured to increase the first epoch specific storage space by the additional space;
• and
• the I/O filter is configured to proceed with the write request to the virtual disk.