1. Overview of Oracle Solaris System Tuning
2. Oracle Solaris Kernel Tunable Parameters
Where to Find Tunable Parameter Information
General Kernel and Memory Parameters
fsflush and Related Parameters
General File System Parameters
sun4u or sun4v Specific Parameters
Solaris Volume Manager Parameters
4. Internet Protocol Suite Tunable Parameters
5. Network Cache and Accelerator Tunable Parameters
A. Tunable Parameters Change History
The Solaris kernel memory allocator distributes chunks of memory for use by clients inside the kernel. The allocator creates a number of caches of varying size for use by its clients. Clients can also request the allocator to create a cache for use by that client (for example, to allocate structures of a particular size). Statistics about each cache that the allocator manages can be seen by using the kstat -c kmem_cache command.
Occasionally, systems might panic because of memory corruption. The kernel memory allocator supports a debugging interface (a set of flags), that performs various integrity checks on the buffers. The kernel memory allocator also collects information on the allocators. The integrity checks provide the opportunity to detect errors closer to where they actually occurred. The collected information provides additional data for support people when they try to ascertain the reason for the panic.
Use of the flags incurs additional overhead and memory usage during system operations. The flags should only be used when a memory corruption problem is suspected.
The Solaris kernel memory allocator has various debugging and test options that were extensively used during the internal development cycle of the Solaris OS. Starting in the Solaris 2.5 release, a subset of these options became available. They are controlled by the kmem_flags variable, which was set with a kernel debugger, and then rebooting the system. Because of issues with the timing of the instantiation of the kernel memory allocator and the parsing of the /etc/system file, it was not possible to set these flags in the /etc/system file until the Solaris 8 release.
Five supported flag settings are described here.
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Signed integer
0 (disabled)
0 (disabled) or 1 - 15 or 256 (0x100)
Yes. Changes made during runtime only affect new kernel memory caches. After system initialization, the creation of new caches is rare.
None
When memory corruption is suspected
Unstable