Lenovo ThinkServer RD330 MegaRAID SAS Software User Guide - Page 394
non-redundant configuration
View all Lenovo ThinkServer RD330 manuals
Add to My Manuals
Save this manual to your list of manuals |
Page 394 highlights
Appendix C: Glossary | MegaRAID SAS Software User Guide initialization IO policy learning cycle load-balancing LKM media error count migration mirroring multipathing name non-redundant configuration NVRAM NVRAM present NVRAM size offline The process of writing zeros to the data fields of a virtual drive and, in fault-tolerant RAID levels, generating the corresponding parity to put the virtual drive in a Ready state. Initialization erases all previous data on the drives. Drive groups will work without initializing, but they can fail a consistency check because the parity fields have not been generated. A virtual drive property indicating whether Cached I/O or Direct I/O is being used. In Cached I/O mode, all reads are buffered in cache memory. In Direct I/O mode, reads are not buffered in cache memory. Data is transferred to cache and the host concurrently. If the same data block is read again, it comes from cache memory. (The IO Policy applies to reads on a specific virtual drive. It does not affect the read ahead cache.) A battery calibration operation performed by a RAID controller periodically to determine the condition of the battery. A method of spreading work between two or more computers, network links, CPUs, drives, or other resources. Load balancing is used to maximize resource use, throughput, or response time. Local Key Management A drive property indicating the number of errors that have been detected on the drive media. The process of moving virtual drives and hot spare drives from one controller to another by disconnecting the drives from one controller and attaching them to another one. The firmware on the new controller will detect and retain the virtual drive information on the drives. The process of providing complete data redundancy with two drives by maintaining an exact copy of one drive's data on the second drive. If one drive fails, the contents of the other drive can be used to maintain the integrity of the system and to rebuild the failed drive. The firmware provides support for detecting and using multiple paths from the RAID controllers to the SAS devices that are in enclosures. Devices connected to enclosures have multiple paths to them. With redundant paths to the same port of a device, if one path fails, another path can be used to communicate between the controller and the device. Using multiple paths with load balancing, instead of a single path, can increase reliability through redundancy. A virtual drive property indicating the user-assigned name of the virtual drive. A RAID 0 virtual drive with data striped across two or more drives but without drive mirroring or parity. This provides for high data throughput but offers no protection in case of a drive failure. Acronym for non-volatile random access memory. A storage system that does not lose the data stored on it when power is removed. NVRAM is used to store firmware and configuration data on the RAID controller. A controller property indicating whether an NVRAM is present on the controller. A controller property indicating the capacity of the controller's NVRAM. A drive is offline when it is part of a virtual drive but its data is not accessible to the virtual drive. Page 394