Product manual

CDA 7 5630 Product Manual
G-6 77 A1 69UP Rev00
M
Media
The disk surface on which data is stored.
Megabyte (MB)
The MB
2
value is based on the convention: 1 MB = 1024x1024 bytes.
The MB
10
value is based on the convention: 1 MB = 1000x1000 bytes.
Mirrored Pair
A logical volume with all data recorded twice, once on each of two different physical devices.
Mirroring
The Symmetrix option that maintains two identical copies of a designated volume on separate
disks. Each volume automatically updates during a write operation. If one disk device fails,
Symmetrix automatically uses the other disk device.
P
Physical Partition (PP)
A physical partition is the smallest unit of disk space that can be allocated in a volume group in an
AIX environment. Any disk space allocated is an integral number of physical partitions. By
default, a PP is 4 MB in size.
Primary Track
The original track on which data is stored. See also Alternate Track.
Promotion
The process of moving data from a track on the disk device to cache slot.
R
Read Hit
Data requested by the read operation is in cache.
Read Miss
Data requested by the read operation is not in cache.
Reconnect
The function that occurs when a target selects an initiator to continue an operation after a
disconnect.
Reconnection
A reconnection exists from the assertion of the BSY signal in a RESELECTION phase until the
next BUS FREE phase occurs. A reconnection can only occur between a target and an initiator.