System Architecture 2-101
Reserved Pages
PAGE_MCHUNK

The ninth reserved page in the root dbspace isPAGE_1MCHUNK. The tenth

reserved page,PAGE_2MCHUNK, is the second page in the pair.

Thetbinit daemon uses the mirror chunk page to describe each mirror

chunk, its pathname, its relation to the dbspace, and its current status.

Belowlisted the mirror chunk fields and definitions. To obtain a listing of the

reserved page, execute the commandtbcheck -pr.

Chunk flags:
0x01
0x02
0x04
0x08
0x20
0x40
0x80
0x100
0x200
0x400
Raw device
Block device
UNIX file
Needs sync() to operating system
Chunk is offline
Chunk is online
Chunk is in recovery
Chunk is newly mirrored
Chunk is part of a blobspace
Chunk is being dropped
Chunk name length Length of the chunk pathname
Chunk path Operating system path for chunk
Field Name Description
Primary chunk number Chunk number
Next chunk in dbspace Number of the next chunk in the dbspace
Chunk offset Offset of chunk, in pages
Chunk size Number of pages in the chunk
Number of free pages Number of free pages in the chunk
Dbspace number Number of this chunk’s dbspace
(1 of 2)
Field Name Description
(2 of 2)