Adaptive Server version 12.5.1 requires Mac OS X 10.3 (Panther), and does not run on older versions of Mac OS X. The primary reason for this is to take advantage of Panther’s asynchronous disk I/O, which is not available on older versions.
The operating system must be configured to allow the necessary number of concurrent asynchronous disk I/Os. This configuration is done automatically by Adaptive Server during the installation, but the configuration is not persistent — the changes do not survive a system restart. To set appropriate kernel configuration values during system startup, see the next section.
Adaptive Server’s use of asynchronous disk I/O is determined by two of Adaptive Server’s configuration properties:
allow sql server async i/o – a switch, which defaults to ON (1). If OFF (0), Adaptive Server will not use the new Panther asynchronous disk I/O capabilities, and your system throughput will be noticeably affected.
disk i/o structures – instructs Adaptive Server to use no more than this number of concurrent, outstanding asynchronous disk I/Os. The default is 256.
When Adaptive Server starts, it sets the kernel properties as follows:
kern.aiomax – the maximum number of system-wide concurrent asynchronous disk I/Os allowed. Adaptive Server sets this to the greater of:
Current value, or
max online engines * disk i/o structures + 128.
kern.aioprocmax – which is the maximum per-process number of concurrent asynchronous disk I/O’s allowed. Adaptive Server sets this to the greater of:
Current value, or
disk I/O structures
If Adaptive Server is not started with sufficient privileges, attempts to set these values will fail. In that case, a number of warning messages will be written to the Adaptive Server error log. This should be avoided in production systems, as this can negatively impact performance. When Adaptive Server is started by the installer, or started during system reboot, it is given sufficient privileges to set these values.
