Mac OS X kernel configuration

There are some kernel configuration items that may be necessary to set during system startup. In addition to the asynchronous disk I/O configuration values mentioned in the previous section, there are also some shared memory configuration values that should be set to enable the striping capability of the Sybase Backup Server. To establish these kernel configuration values during system startup, the file located at:


should be modified as follows:

#	Configure additional async io resources.  Change if
#   ASE's config value for
#	"disk i/o structures" is changed to exceed 1024.
/usr/sbin/sysctl -w kern.aiomax=2048
/usr/sbin/sysctl -w kern.aioprocmax=1024
/usr/sbin/sysctl -w kern.aiothreads=16

exit 0

In addition to the asynchronous disk I/O configuration, it may also be necessary to configure more than the default amount of shared memory. The Sybase Backup Server uses SystemV shared memory when performing dump/load operations, and the amount can vary, depending on the degree of striping specified during the operation. If changes are needed, a single file can be modified to specify the shared memory configuration. This file is at /etc/rc. The file sets up a default amount of shared memory, using the following commands:

sysctl -w kern.sysv.shmmax=4194304
sysctl -w kern.sysv.shmmin=1
sysctl -w kern.sysv.shmmni=32
sysctl -w kern.sysv.shmseg=8
sysctl -w kern.sysv.shmall=1024

These defaults can be modified as needed; we suggest a multiple of 10 for shmmax, shmmni, shmseg, shmall. This should be sufficient for most uses of shared memory by the Backup Server.