Through this configuration option, you can specify an upper limit on the size of the cache in MB. The number of items in the cache are limited by maximum size of the cache and amount of free system memory (virtual or physical). If some eviction policy is specified, whenever total data size in cache reaches maximum size or when less than 10% of memory is left in the system, items are removed from the cache as per eviction policy. Maximum size of a cache can be specified by following ways:
Using NCache Web Manager
Launch NCache Web Manager by browsing to
<server-ip>:8251(Windows + Linux).
In the left navigation bar, click on Clustered Caches or Local Caches, based on the cache server to start. Against the cache name, click on View Details.
This opens up the detailed configuration page for the cache.
In the Overview tab, click on the button.
Change the Max Cache Size which is in MBs.
Click on to save the cache configuration.
New-Cache cmdlet enables the user to create a new cache on one or more server nodes.
This command creates a local cache of size 1024MB on test1 node. Here, instead of 1024, any size can be mentioned.
New-Cache demoCache -Server test1 -Size 1024
Manually Editing NCache Configuration
Make sure the cache is stopped before making any configuration changes.
You can specify the Cache Size through config.ncconf by specifying the
<storage> tag under the
<cache-settings cache-name="this" alias="" inproc="False" last-modified="" auto-start="True" data-format="Binary"> ... <storage type="heap" cache-size="1024mb"/> ... </cache-settings>
- Once changes are made, start the cache and restart NCache service.
Out of Memory Problem
This usually happens when Maximum Size for the cache is not specified correctly. Often, processing overhead is not kept into consideration while specifying the Maximum Size.
In order to resolve out of memory issue, NCache has provided a memory based cache, where you can specify an upper limit on the size of the cache in MB. Please specify correct Maximum Size for your cache. You should specify a Maximum Size which, if completely consumed, still leaves enough space in the system so that it never goes under low resources.
While specifying the cache size, consider the following factors:
- Average size of Sessions or Objects.
- Number of expected Sessions or Objects.
- Available memory for the NCache process.
Then you can calculate the required memory by keeping the following in mind.
- 15% Overhead per session.
- 15-20% overhead for processing. If object size is greater than 80KB, this ratio may be little bit high.