NetBase SQL Shadowing Handbook

NetBase SQL Installation
____________________________________________________________
ver A0195 QUEST Software, Inc. 2-21
7. Add Additional Required Log Files
Once WSL is enabled, you have created a single log file. WSL requires a minimum of
two log files. To add additional log files, you should run SQLUtil.
1. Run SQLUtil.
:SQLUTIL
>> ADDLOG
DBEnvironment Name: <<your dbe's name>>
Maintenance Word: <CR>
Name of Log file: <<your log file's name>>
Size of Log file: <<size in pages>>
Okay to add? Y
>> EXIT
The ADDLOG command creates additional log files either in archive mode or non-
archive mode, depending on the mode of the DBE. If your DBE is in archive mode (as
your master DBE should be), the ADDLOG command will create archive log files. If your
DBE is in non-archive mode (as your shadow machine may be), the resulting log files
will be created as non-archive ones.
Non-archive log files are circular files which cannot be used for data recovery. Their
size must be sufficient to handle the maximum number of concurrent transactions. You
may use non-archive log files on your shadow systems only.
Archive log files are required for disaster recovery, and they are recommended on the
master machine. Archive log files contain records for every addition, modification, or
deletion of a tuple in the DBE. Archive log files retain this information until they are
backed up using the STORE command in SQLUtil. Consequently, your system must
have enough log files to accommodate all transactions between backups.
Sizing Log Files
If the space allocated for log files is inadequate, a LOG FULL condition will occur. If it is
on the shadow side, the transactions will be queued on the master, but they will not be
applied to the shadow. Additionally the import process on the shadow machine will be
stopped. If LOG FULL happens on the master machine, processing will halt.
Sizes of archive and non-archive log files are stated in log pages. A log page is 512
bytes. You may build a maximum of 36 log files per DBE, and the maximum size of a
log file is currently 524.287 pages.
The size of a non-archive log file may be calculated as follows:
[(Max. size of a transaction ) x (Max. Number of Concurrent Transactions)] + 38
pages
Max. size of a transaction =
[(DBE size in pages) x (%inserted + %deleted + %changed) x 2] / 500 bytes per
page