Patent ID: 9594510
Date: 2017-03-14
CPC Classifications: G06F

Claim:
1. A computer system comprising: a host entity for issuing IO requests; an external JBOD (just a bunch of disks) emulation controller coupled to the host entity for emulating IO operations in response to the IO requests; and a group of physical storage devices (PSDs) coupled to the JBOD emulation controller each through a point-to-point serial-signal interconnect for providing storage to the computer system through the JBOD emulation controller in which each of the PSDs is a hard disk drive (HDD) or a solid state drive (SSD), wherein said JBOD emulation controller defines at least one logical media unit (LMU) comprising sections of said group of PSDs, and is configured to provide a mapping that maps combination of the sections of said group of PSDs to the at least one LMU visible to the host entity, and the at least one LMU is contiguously addressable by the host entity to which the at least one LMU is made available, and said JBOD emulation controller performs the following functions: bringing the whole LMU on line such that the whole LMU is accessible by the host entity, while the JBOD emulation controller is on line, and while a requisite quorum of said PSDs becomes on-line, in which the requisite quorum refers to said group of PSDs of the whole LMU data of which is accessible correctly by the JBOD emulation controller while at least one PSD of said PSDs is inaccessible; and taking the whole LMU off line such that the whole LMU is inaccessible by the host entity, while the JBOD emulation controller is on line, and while all the requisite quorum of said PSDs is not on line, in which on line PSDs of said PSDs are less than the requisite quorum of said PSDs; wherein said external JBOD emulation controller comprises a central processing circuitry for performing said IO operations in response to said IO requests of said host entity; at least one IO device interconnect controller coupled to said central processing circuitry; at least one host-side IO device interconnect port provided in one of said at least one IO device interconnect controller for coupling to said host entity; and at least one device-side IO device interconnect port provided in one of said at least one IO device interconnect controller for coupling to one of said PSDs; and wherein the IO requests are parsed to determine what operation is to be performed and on which sections of the LMU the operation is to be performed; wherein when the operation comprises internally-emulated, asynchronous device sub-operations, then the JBOD emulation controller executes the associated sub-operations including transferring any associated data to/from the host entity; and wherein when there is a failed operation, the JBOD emulation controller generates a status report and responds to the host entity with the status report indicating that the operation failed.