Abstract: Methods, apparatus, and systems, including computer programs encoded on a computer storage medium, manage metadata for virtual volumes. In some implementations, a method includes: loading into memory at least a portion of metadata for a virtual volume (VV) that spans data extents of different persistent storage devices, wherein the metadata comprises virtual metadata block (VMB) descriptors and virtual metadata blocks (VMBs); mapping an address of the VV to a VMB number and an index of an extent pointer within a VMB identified by the VMB number, wherein the extent pointer indicates an extent within one of the different persistent storage devices; locating a VMB descriptor in the memory based on the VMB number; and locating the identified VMB in the memory or not in the memory based on the located VMB descriptor.

Abstract: Methods, systems, and apparatus, including computer programs encoded on a computer storage medium, for managing metadata for pools of storage disks, are described. In some implementations, a system includes a processor, a memory and a storage system. The storage system contains a storage pool including multiple storage devices. Further, the storage system is configured to store in persistent storage associated with the storage pool a bitmap that is configured to indicate whether metadata blocks corresponding to one or more virtual volumes associated with the storage pool are free or occupied. In addition, the processor is configured to perform operations including accessing at least portions of the bitmap, and managing, based on information from the accessed portions, at least some of the metadata blocks stored in the persistent storage.

Abstract: Methods, apparatus, and systems, including computer programs encoded on a computer storage medium, manage metadata for virtual volumes. In some implementations, a method includes: loading into memory at least a portion of metadata for a virtual volume (VV) that spans data extents of different persistent storage devices, wherein the metadata comprises virtual metadata block (VMB) descriptors and virtual metadata blocks (VMBs); mapping an address of the VV to a VMB number and an index of an extent pointer within a VMB identified by the VMB number, wherein the extent pointer indicates an extent within one of the different persistent storage devices; locating a VMB descriptor in the memory based on the VMB number; and locating the identified VMB in the memory or not in the memory based on the located VMB descriptor.

Abstract: Methods, systems, and apparatus, including computer programs encoded on a computer storage medium, manage metadata for virtual volumes. In some implementations, a method and system include defining multiple metadata blocks in a persistent storage, including information that links a virtual address space to the storage system, where the defining includes, for at least one of the multiple metadata blocks, determining multiple output addresses corresponding to the storage system, and writing the multiple output addresses and an identifier corresponding to the multiple metadata blocks in a metadata block in the persistent storage. In some implementations, a method and system include reading the multiple metadata blocks into the memory from the persistent storage, including identifying the metadata block based on the identifier; receiving an input address of the virtual address space; and obtaining a corresponding output address to the storage system using the multiple metadata blocks in the memory.

Abstract: Methods, systems, and apparatus, including computer programs encoded on a computer storage medium, manage metadata for virtual volumes. In some implementations, a method and system include defining multiple metadata blocks in a persistent storage, including information that links a virtual address space to the storage system, where the defining includes, for at least one of the multiple metadata blocks, determining multiple output addresses corresponding to the storage system, and writing the multiple output addresses and an identifier corresponding to the multiple metadata blocks in a metadata block in the persistent storage. In some implementations, a method and system include reading the multiple metadata blocks into the memory from the persistent storage, including identifying the metadata block based on the identifier; receiving an input address of the virtual address space; and obtaining a corresponding output address to the storage system using the multiple metadata blocks in the memory.