Technique for managing addition of disks to a volume of a storage system
View Patent ↗A technique manages the addition of disks to a volume of a storage system. A disk addition procedure is encapsulated into a DISKADD object conforming to a configuration management framework used to implement a RAID subsystem of the storage system. The DISKADD object is responsible for determining a set of available disks required to satisfy a disk addition request issued by an operator through a user interface of a storage operating system executing on the storage system. Furthermore, the DISKADD object is responsible for monitoring the state of the disks, including preparation/initialization of the disks (e.g., disk zeroing) and possible disk failures, as well as placing those disks into RAID groups of the volume once preparation completes. Persistent storage of the state of a pending disk addition is then accomplished using an implementation of the configuration management framework.
1. A method for managing addition of disks to a volume of a storage system, comprising:
implementing a redundant array of independent disks (RAID) subsystem in a storage operating system of the storage system using a configuration management framework that provides a configuration tree adapted to organize a plurality of objects;
issuing a disk addition request through a user interface of the storage operating system to the RAID subsystem, the disk addition request selecting a count of available disks to be added to the volume;
adding and allocating the selected disks to a disk container object associated with a disk addition (diskadd) object of the configuration tree, the diskadd object encapsulating a placement procedure;
rendering an initial disk placement decision using the placement procedure;
inserting the allocated disks into a RAID group of the volume;
zeroing the allocated disks in accordance with a zeroing process;
determining whether an allocated disk fails during the zeroing process;
if an allocated disk fails, issuing a failure notification from the disk container object to the diskadd object;
determining whether an atomic mode of disk addition is specified by the disk addition request;
if the atomic mode is specified, aborting the disk addition request in response to the failure notification;
if the atomic mode is not specified, discarding the failed allocated disk;
continuing the zeroing process with remaining allocated disks;
associating the inserted disks as disk objects with respect to a RAID group object of the configuration tree to render the inserted disks capable of storing data; and
destroying the diskadd and disk container objects in accordance with a destroy method of each object.
2. The method of claim 1 wherein the step of inserting the allocated disks comprises:
assigning the inserted disks as either data or parity disks; and
for each data disk, assigning a block range.
3. The method of claim 2 further comprising: removing the selected disks from a spare pool of the storage system.
4. The method of claim 1 , wherein the atomic mode requires all disks to be added to the volume or none of the disks are added to the volume.