22
FLASH
MEDIA
SERVER
4.5
CONFIGURATION
AND
ADMINISTRATION
Configuring the server
Last updated 11/28/2012
2
Edit the
SERVER.FLVCACHE_MAXSIZE
parameter.
This is the maximum size of the cache, in megabytes. The default value is 500. The file cache shares process address
space with the core process. Each core process has a separate file cache. For 32-bit processes, it has a limit of 2 GB
in Windows and 3 GB in Linux. For 64-bit installations, the limit is greater. For more information, see “
Configure
a 64-bit server
” on page 21.
The size of the cache limits the number of unique streams the server can publish. To increase the probability that a
requested stream will be located in the recorded media cache, increase the value of
SERVER.FLVCACHE_MAXSIZE
.
To decrease the amount of memory the server process uses, decrease the value of
SERVER.FLVCACHE_MAXSIZE
.
While a large cache size is useful, Adobe recommends that you ensure that your total system memory usage does
not exceed the process limit of your OS. Consider memory limits and desired memory and stream performance
when utilizing the memory cache.
Note:
Cache settings have no effect on live streams, as live streams do not need or utilize the cache.
3
Restart the server.
There is no exact way to calculate the value of the cache size because it varies depending on the amount of RAM
available and the number of other processes that are running. However, you can follow some general guidelines to
approximate the recommended size of the cache.
Out of the total system RAM, some amount will be used by the OS and other non-Flash Media Server processes:
Amount of RAM available for FMS (R) = RAM size - RAM used by the OS and non-FMS processes
The RAM available for Flash Media Server is divided among the number of cores started:
Amount of RAM per core (Rc) = Amount of RAM available for FMS (R) / Number of Cores
Out of this, some amount of RAM is used up by the core process, and is not available to the file cache:
Recommended File Cache Size = Amount of RAM per core (Rc) - RAM used by each core process
RAM used by each Flash Media Server process varies based on load, and there is no exact figure. You can use 512 MB
as a ballpark figure.
The following example attempts to determine a reasonable file cache size:
RAM size = 8 GB
RAM used by OS and non-FMS processes = 1.2 GB (approximately)
Number of FMS core processes allowed = 3
Amount of RAM available for FMS (R) = 8 - 1.2 = 6.8
Amount of RAM per core (Rc) = 6.8 / 3 = 2.27 GB
Recommended file cache size = 2.27 - 0.5 = 1.76 GB
Configure the size of stream chunks
Streams break into chunks as they are written to the network. You can specify the size of a chunk. Large values reduce
CPU usage because there are fewer writes. However, large values can delay other content on lower bandwidth
connections. The larger the content size and the higher the bandwidth of the receiving connection, the more benefit is
gained from larger chunk sizes.
1
Open the Application.xml file.
Note:
You can set these values in an Application.xml file at the VHost level or at the application level. To set the value
at the application level, copy an Application.xml file to the application’s folder.
2
In the
Client
element, set the
OutChunkSize
element to a value between 128 and 65536 bytes. The default value
is 4096 bytes.