When initially
starting NAS, NAS identifies the location of an empty log file for each
kjs where NAS writes information about the state of all ongoing distributed
transactions for that process. NAS then creates additional files called
restart and r estart.bak (a backup of restart )
for each kjs. These files record the location of the log file and the
state of the logical and physical volumes. Once created, NAS refers
to the restart file for the location and state of the log file each
time the server restarts. NAS stores the restart and restart.bak
in the root and mirror directories listed on the Configuration tab.
These files should
be stored on different devices if possible. If both restart and
restart.bak become corrupted, the transaction manager becomes
inoperable and the administrator must cold start the server. When cold
starting a server, NAS looks to the registry for the location of the
log file and overwrites the existing log file.
Log files can be
either raw partitions or simple files. The install program creates file
system based on logs only. The default size of transaction logs is 4
megabytes on a Solaris system.
The transaction
monitor periodically checks the logs and discards old transactions that
are complete. This service is built into the transaction monitor and
is not configured.
The left pane of
the Transaction screen displays a tree of nodes. The first level shows
a registered NAS server, and the second level displays engine nodes.
There is one engine node for each running kjs. Only Java engines (kjs)
appear in the tree because only kjs engines support transactions.
The third level
of the tree displays the physical volumes for each process. Click on
the icon for more detail. The page size of a page used in the transaction
manger, the total size of the physical volume, and the amount of unused
disk space in the physical volume is shown. You cannot edit these values.
The fourth level
of the tree displays disk properties. A disk can be thought of as a
partition of the physical volume. You can create an unlimited number
of disks, but you cannot delete a disk after it is created. Click on
the disk node icon to display the location and size of the selected
disk.