Calculating Rollover Requirements - Novell ACCESS MANAGER 3.1 SP1 - GATEWAY GUIDE Manual

5 Design a log deletion strategy
The Access Gateway has a limited amount of disk space allocated for logging, and you need to
decide how you are going to manage this space. You can limit the number of rollover files by
number or age. You can also select to copy the files to another server and then delete them. To
calculate the best procedure, see
page 111.

4.2.2 Calculating Rollover Requirements

You can have the Access Gateway roll over log files based on time or on size, but not both. If you
already know which option you want to use, scan this section and then complete only the
calculations pertinent to your choice. If you don't know which option best matches your situation,
completing the calculations in this section should help you decide.
The following variables are used in the formulas:
logpartition_size: The total disk capacity reserved for log files on the Access Gateway.
The Access Gateway reserves 4 GB to share between logging and system files. The system files
do not grow significantly, so you can assume that you have about 2 GB for logging. To increase
this size, see Section 4.2.6, "Configuring the Size of the Log Partition," on page
logentry_size: The average log entry size.
You can determine this by configuring a proxy service to track the required information,
generating traffic to the proxy service, downloading the log files, determining how large each
entry is, and calculating the average.
request_rate: The peak rate of requests per second.
You can estimate this rate or place your Access Gateway in service and get more accurate data
by accessing generated statistics. See
page 118.
num_services: The number of proxy services for which you plan to enable logging.
logs_per_service: The number of log files, both active and closed, that you want the Access
Gateway to generate for each proxy service before the disk fills.
You must plan to have at least two logs per proxy service, but you can have three or more.
The following formulas can help you estimate when the system would run out of resources:
"Calculating diskfull_time" on page 111
"Calculating max_roll_time" on page 112
"Calculating max_log_roll_size" on page 112
Calculating diskfull_time
Use the following formula to calculate how long it will take the Access Gateway to fill your logging
disk space:
diskfull_time in seconds = logpartition_size / (request_rate *
logentry_size * num_services)
For example, assume the following:
logpartition_size = 1 GB (1,073,741,824 bytes)
Section 4.2.2, "Calculating Rollover Requirements," on
Section 4.3, "Monitoring Access Gateway Statistics," on
118.
Access Gateway Maintenance 111