Lenovo ThinkServer RD330 MegaRAID SAS Software User Guide - Page 396
A controller attribute indicating the current Read Policy mode. In Always Read Ahead
View all Lenovo ThinkServer RD330 manuals
Add to My Manuals
Save this manual to your list of manuals |
Page 396 highlights
Appendix C: Glossary | MegaRAID SAS Software User Guide read policy rebuild rebuild rate reclaim virtual drive reconstruction rate redundancy redundant configuration revertible hot spare revision level SAS SATA SCSI device type serial no. strip size stripe size A controller attribute indicating the current Read Policy mode. In Always Read Ahead mode, the controller reads sequentially ahead of requested data and stores the additional data in cache memory, anticipating that the data will be needed soon. This speeds up reads for sequential data, but there is little improvement when accessing random data. In No Read Ahead mode (known as Normal mode in WebBIOS), read ahead capability is disabled. The regeneration of all data to a replacement drive in a redundant virtual drive after a drive failure. A drive rebuild normally occurs without interrupting normal operations on the affected virtual drive, though some degradation of performance of the drive subsystem can occur. The percentage of central processing unit (CPU) resources devoted to rebuilding data onto a new drive after a drive in a storage configuration has failed. A method of undoing the configuration of a new virtual drive. If you highlight the virtual drive in the Configuration Wizard and click Reclaim, the individual drives are removed from the virtual drive configuration. The user-defined rate at which a drive group modification operation is carried out. A property of a storage configuration that prevents data from being lost when one drive fails in the configuration. A virtual drive that has redundant data on drives in the drive group that can be used to rebuild a failed drive. The redundant data can be parity data striped across multiple drives in a drive group, or it can be a complete mirrored copy of the data stored on a second drive. A redundant configuration protects the data in case a drive fails in the configuration. When you use the Replace Member procedure, after data is copied from a hot spare to a new drive, the hot spare reverts from a rebuild drive to its original hot spare status. A drive property that indicates the revision level of the drive's firmware. Acronym for Serial Attached SCSI. SAS is a serial, point-to-point, enterprise-level device interface that leverages the Small Computer System Interface (SCSI) protocol set. The SAS interface provides improved performance, simplified cabling, smaller connectors, lower pin count, and lower power requirements when compared to parallel SCSI. Acronym for Serial Advanced Technology Attachment. A physical storage interface standard. SATA is a serial link that provides point-to-point connections between devices. The thinner serial cables allow for better airflow within the system and permit smaller chassis designs. A drive property indicating the type of the device, such as drive. A controller property indicating the manufacturer-assigned serial number. The portion of a stripe that resides on a single drive in the drive group. A virtual drive property indicating the length of the interleaved data segments that the RAID controller writes across multiple drives, not including parity drives. For example, consider a stripe that contains 64 KB of drive space and has 16 KB of data residing on each drive in the stripe. In this case, the stripe size is 64 KB and the strip size is 16 KB. The user can select the stripe size. Page 396