Electrical computers and digital processing systems: memory – Storage accessing and control – Control technique
Reexamination Certificate
2002-05-08
2004-11-09
Moazzami, Nasser (Department: 2187)
Electrical computers and digital processing systems: memory
Storage accessing and control
Control technique
C711S114000, C707S793000, C714S006130
Reexamination Certificate
active
06816950
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention is generally directed toward a method and an apparatus for upgrading a disk in a storage system. More specifically, the present invention is directed to upgrading firmware within a disk of a Redundant Array of Independent Disks (RAID) storage system.
2. Discussion of Related Art
A Redundant Array Of Independent Disks (RAID) storage system typically stores redundant information across multiple disks. The information includes redundant data provided by a host system as well as redundant data generated and managed by the RAID storage system. The generation and management of the redundant information are transparent to the host system. The redundant information is used to enhance the reliability and/or performance of the storage system. For example, when information is lost on one disk of the array, the storage system may continue to operate using the redundant information managed by the storage system on other disks of the array.
An example of a single disk in the array is a hard disk drive as typically found in a personal computer. Access to data on the disks is gained through input/output (I/O) operations, such as reading and writing. Storage controllers that are usually internal to the storage subsystem process these I/O operations. A user working in a host operating system environment of a computer views the multiple disks as a single disk because the redundant information generated and utilized by the RAID storage system and the distribution of information over multiple disks is independent of, and transparent to, the host operating system that is coupled to the RAID storage system.
Since information is redundantly stored, the RAID storage system can operate in a reduced or degraded mode that allows users to continue accessing the information despite a temporary loss of one of the disk drives in the array. The missing information associated with the inoperable disk drive may be constructed from the redundant information stored on the other disk drives of the array. The redundant information stored in other disk drives of the array may also be used to reconstruct the missing information upon reinitialization, repair, or replacement of the lost drive. The RAID storage system structure and operation increases the mean-time-between-failures (MTBF) and makes the RAID storage system more fault tolerant.
The RAID storage system typically includes one or more controllers that provide overall management of the array of disks including communications with attached host operating systems and processing of input/output requests received from the attached host operating systems. These RAID controllers usually include programmable elements, such as processors, that are programmed with instructions, such as software or firmware. The programmed instructions operate the programmable elements of the RAID controllers. In a similar manner, the individual disks of the array often include lower level programmable controller elements for operational control of one corresponding disk.
Occasionally, disk manufacturers develop improvements, or upgrades, to the disks of the RAID storage system. The improvements, or upgrades, often include changes to the programmed instructions that are operable within a microcontroller or processor that controls an individual disk. The improvements can also include downgrades when problems are detected with recently installed firmware. As used herein, “upgrade” refers to any modification of the firmware of the disk drive whether the modification is strictly speaking an upgrade of features or a downgrade to restore a previous version of firmware. A firmware upgrade installation to the disk involves removing the disk from operation of the RAID storage system. One approach to installing the firmware of the disks includes removing the entire RAID storage system from operation while each disk in the RAID storage system has new firmware installed. This process can be time consuming since a RAID storage system typically includes many disks from the same manufacturer. Upon completion of a firmware installation, the RAID storage system is again made operable. An inoperable RAID storage system is unacceptable in many business environments that demand high reliability and availability of the storage system. For example, a security system using a RAID storage system that becomes unavailable during a period of upgrading would be unacceptable since security breaches may occur during such a “down” time.
Another method of upgrading firmware of the disks of an array includes disabling one disk at a time, thereby placing the RAID storage system in a degraded mode rather than a totally inoperable mode. The RAID storage system can remain in operation while the disk is upgraded with new firmware instructions. Once the firmware upgrade for one disk is complete, present methods reconstruct all data on the disk from redundant data on other disks in the RAID storage system. However, this process of reconstruction for even a single disk drive is time consuming, especially on modern, high-density, large capacity disks. Furthermore, the RAID storage system must continue to operate in a degraded mode until the data is reconstructed further complicating the reconstruction process.
As evident from the above discussion, a need exists for improved structures and methods for modifying the firmware in disk drives of a RAID storage system so as to reduce “down” time.
SUMMARY OF THE INVENTION
The present invention solves the above and other problems and advances the state of the useful arts by providing an apparatus and a method for upgrading firmware on a disk of the array without a need for total reconstruction of the data on an upgraded disk. More specifically, the present invention provides for logging information regarding write operations directed to the disk being upgraded while the single disk is inoperable during the upgrade process. When the upgrade of the disk is complete, the logged information is used to update the information stored on the upgraded disk. The logged information is sufficient to update the disk contents without requiring a time consuming total reconstruction of the entire content of the disk. In one exemplary preferred embodiment, the logged information identifies a logical block numbers of the disk that are impacted by write operations processed while the disk firmware was being upgraded. Only the data corresponding to the logged logical block numbers need be reconstructed from the redundant data on other disks of the array. This method of data reconstruction is a less time consuming process than a total reconstruction of all data on the upgraded disk.
In a second exemplary preferred embodiment, the logged information includes details of the write operations processed while the disk firmware was being upgraded. The write operations impact the stored content of the upgraded disk. The details of the write operations are preferably sufficient to permit the RAID storage controller to re-process the request to the extent it impacts the stored data on the upgraded disk. This second exemplary embodiment may require additional storage as compared to the first exemplary embodiment because the data to be written is stored with the logged write operations. However, this second exemplary embodiment may be faster as compared to the first exemplary embodiment because it need not access redundant information on other disks of the array to update the data stored on the upgraded disk. The updated data is simply written to the upgraded disk rather than reconstructed from redundant data stored on other disks of the array.
In an exemplary preferred embodiment of the invention, a method and a system for programming firmware instructions into a disk-drive controller of a first disk within a plurality of disks is provided. A system includes a data router for routing update requests of the first disk. The system also includes a storage component communicatively connected to the data router for logging the update requests i
Duft Setter Ollila & Bornsen LLC
LSI Logic Corporation
Moazzami Nasser
LandOfFree
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