Name

SSLSessionCache

Synopsis

SSLSessionCache type
SSLSessionCache none
Server config
Apache v2 only

This configures the storage type of the global/interprocess SSL Session Cache. This cache is an optional facility that speeds up parallel request processing. SSL session information, which are processed in requests to the same server process (via HTTP keepalive), are cached locally. But because modern clients request inlined images and other data via parallel requests (up to four parallel requests are common), those requests are served by different preforked server processes. Here an interprocess cache helps to avoid unnecessary session handshakes.

The following storage types are currently supported:

none

This is the default and just disables the global/interprocess Session Cache. There is no drawback in functionality, but a noticeable drop in speed penalty can result.

dbm:/path/to/datafile

This makes use of a DBM hashfile on the local disk to synchronize the local OpenSSL memory caches of the server processes. The slight increase in I/O on the server results in a visible request speedup for your clients, so this type of storage is generally recommended.

shm:/path/to/datafile[( size )]

This makes use of a high-performance hash table (approximately size bytes big) inside a shared memory segment in RAM (established via /path/to/datafile) to synchronize the local OpenSSL memory caches of the server processes. This storage type is not available on all platforms.

Examples

SSLSessionCache ...

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