This article contains information about setting the Integrated Caching memory limits on a NetScaler appliance.

Requirements

The following are the basic requirements to perform this task:

Background

In the NetScaler software releases earlier than the NetScaler nCore software release 9.1, the NetScaler appliance was limited to using no more than 4 GB of memory. Additionally, the cache was limited to the half of the total memory. As a result, you cannot allocate more than 2 GB of memory for caching. In some setups, this was not sufficient to cache the frequently accessed Web pages.

Starting NetScaler nCore software release 9.1, you can allocate more memory to the cache. On appliances with more than 4 GB of memory, you can allocate additional memory for cache.

Instructions

For setting the Integrated Caching memory limits on a NetScaler appliance, complete the following procedure:

1.  Switch to the shell prompt.

2. Run the following command to determine the amount of memory you can allocate for caching without any impact on other functions:
   nsconmsg –K /var/nslog/newnslog –g mem_cur_freesize –d minvalue

   This command displays the lowest free memory available. You must run this command to cover a large timeframe to ensure that it covers the abnormally high memory allocations, if any.

   The following is a sample output of the command for your reference:

   Displaying minimum value information
   NetScaler V20 Performance Data
   NetScaler NS9.2: Build 39.6.nc, Date: Mar 18 2010, 15:54:59
   Index value symbol-name&device-no&time
   0 12564065360 mem_cur_freesize_actual Wed Apr 14 21:35:59 2010
   1 12078658016 mem_cur_freesize Wed Apr 14 12:37:53 2010

3. Note the value of the mem_cur_freesize parameter and deduct at least 10 percent of the total memory from it to account for the grown and unusual memory usage.

4. Switch to the NetScaler command line interface prompt.

5. Run the following command to verify the current memory allocation and amount of memory that can be used:
   ns1_nCore> show cache parameter

   Integrated cache global configuration:
   Memory usage limit: 2047 Mbytes
   Memory usage limit (active value): 2044 Mbytes
   Maximum value for Memory usage limit: 15772 Mbytes
   Via header: NS-CACHE-8.0: 230
   Verify cached object using: HOSTNAME_AND_IP
   Max POST body size to accumulate: 4096 bytes
   Current outstanding prefetches: 0
   Max outstanding prefetches: 4294967295
   Treat NOCACHE policies as BYPASS policies: YES
   Global Undef Action: NOCACHE
   Done

6. Run the following command to set the new memory limit:
   ns1_nCore> set cache parameter -memLimit 10000

   You can use the maximum of the values you calculated in Step 3 of the one available in the Step 5. In this procedure, the memory limit is set to 10000 MB.

7. Save the configuration.

8. Restart the appliance to make the changes effective.
   Starting NetScaler software release 9.2 and later, you can also run reboot –warm.

9. Run the following command to verify the memory allocation:
   ns1_nCore> show cache parameter

   Integrated cache global configuration:
   Memory usage limit: 10000 Mbytes
   Memory usage limit (active value): 10000 Mbytes
   Maximum value for Memory usage limit: 15772 Mbytes
   Via header: NS-CACHE-8.0: 230
   Verify cached object using: HOSTNAME_AND_IP
   Max POST body size to accumulate: 4096 bytes
   Current outstanding prefetches: 0
   Max outstanding prefetches: 4294967295
   Treat NOCACHE policies as BYPASS policies: YES
   Global Undef Action: NOCACHE
   Done

10. Run the following command to verify the complete detail of the Integrated Caching statistics:
    ns1_nCore> stat cache –detail

    Integrated Cache Statistics – Detail
    Integrated Cache Statistics – Summary
    Rate (/s) Total
    Hits 0 0
    Misses 0 0
    Requests 0 0
    Hit ratio(%) -- 0
    Origin bandwidth saved(%) -- 0
    Cached objects -- 0
    Marker objects -- 0
    Rate (/s) Total
    Requests 0 0
    
    Hit Statistics
    Rate (/s) Total
    Non-304 hits 0 0
    304 hits 0 0
    Hits 0 0
    304 hit ratio(%) -- 0
    Hit ratio(%) -- 0
    Origin bandwidth saved(%) -- 0
    
    Byte Statistics
    Rate (/s) Total
    Bytes served by NetScaler 0 0
    Bytes served by cache 0 0
    Byte hit ratio(%) -- 0
    Compressed bytes from cache 0 0
    
    Miss Statistics
    Rate (/s) Total
    Storable misses 0 0
    Non-storable misses 0 0
    Misses 0 0
    Revalidations 0 0
    Successful revalidations 0 0
    Conversions to conditional req 0 0
    Storable miss ratio(%) -- 0
    Successful reval ratio(%) -- 0
    
    Flashcache Statistics
    Rate (/s) Total
    Expire at last byte 0 0
    Flashcache misses 0 0
    Flashcache hits 0 0
    
    Invalidation Statistics
    Rate (/s) Total
    Parameterized inval requests 0 0
    Full inval requests 0 0
    Inval requests 0 0
    
    Parameterized Caching Statistics
    Rate (/s) Total
    Parameterized requests 0 0
    Parameterized non-304 hits 0 0
    Parameterized 304 hits 0 0
    Total parameterized hits 0 0
    Parameterized 304 hit ratio(%) -- 0
    
    Poll Every Time (PET) Statistics
    Rate (/s) Total
    Poll every time requests 0 0
    Poll every time hits 0 0
    Poll every time hit ratio(%) -- 0
    
    Memory Usage Statistics
    Total
    Maximum memory(KB) 10240000
    Maximum memory active value(KB) 10240000
    Utilized memory(KB) 14
    Memory allocation failures 0
    Largest response so far(B) 0
    Cached objects 0
    Marker objects 0
    
    Hits being served 0
    Misses being handled 0
    
    Done

You can use the value of the Utilized Memory parameter to determine is an access memory is allocated for caching. You should verify this value when you expect that the cache is being completely utilized.

Citrix Documentation - Integrated Caching