Dell PowerEdge RAID Controller 6E - Manual (Page 145)

Glossary
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Logical Disk
A set of contiguous chunks on a physical disk. Logical disks are used in array
implementations as constituents of logical volumes or partitions. Logical disks
are normally transparent to the host environment, except when the array
containing them is being configured.
M
MB
Acronym for megabyte(s). The term megabyte means 1,048,576 bytes (2^20 bytes);
however, when referring to hard drive storage, the term is often rounded to
mean 1,000,000 bytes.
Mirroring
The process of providing complete redundancy using two physical disks, by
maintaining an exact copy of one physical disk’s data on the second physical
disk. If one physical disk fails, the contents of the other physical disk can be
used to maintain the integrity of the system and to rebuild the failed physical
disk.
Multi-bit ECC Errors
ECC errors are errors that occur in the memory, which can corrupt cached data
so that it has to be discarded. ECC double-bit errors are serious, as they result in
corrupted data and data loss. In case of double-bit ECC errors, contact Dell
Technical Support.
Multi-pathing
PERC 6 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.
Dell_PERC6.2_UG.book Page 145 Wednesday, June 24, 2009 6:08 PM