reduce the File Cache in HP-UX 11.31

[mrmo07]

Hi expart,

our  production is  runnin with HPUX v3. noticed ,  File Cache size is too high, that is  8 GB where total memory is 24 GB.

we want to reduce the filecache_max and filecache_min to reduce file cache size. please share the steps to do it. 

is it ok we only do :

# kctune  filecache_max=3%

# kctune  filecache_min=2%

please help with details.

Regards,

Morshed.

[Dennis Handly]

>please share the steps to do it. 

Looks fine but I would reduce filecache_min first.

[mrmo07]

Hi  Dennis,

currently in our applicatoin server default max file cache is 12 GB ( 24 GB total memory). sometime it is using 10GB as file cache. so total system memory utilization become above 90%.  can we  release file cache somehow without minimizing the size through kernel parameter.

Regards,

Morshed.

[Dennis Handly]

>can we release file cache somehow without minimizing the size through kernel parameter?

If you make filecache_min smaller, the kernel will automatically adjust the filecache if the system is under memory pressure.

Note: Using 90% of memory is a good thing, until you start using swap.

[mrmo07]

Hi,

below is the glance output of my application server. memory utilizaton is 93 % where file cache is 11.4 GB. what to do ? please advice.

 Glance 11.00.044               13:41:03 dcpapp01     ia64    Current  Avg  High
--------------------------------------------------------------------------------
CPU  Util   SU                                                 |  2%    9%   17%
Disk Util   F                                                  |  2%    2%    2%
Mem  Util   S                SU   UF                      F    | 93%   93%   93%
Swap Util   U         UR  R                                    | 29%   29%   29%
--------------------------------------------------------------------------------
 
Total VM :   3.2gb   Sys Mem  :   8.7gb   User Mem:   2.1gb   Phys Mem :  24.0gb
Active VM:   2.7gb   Buf Cache:     0mb   Free Mem:   1.8gb   FileCache:  11.4gb

root@dcpapp01 [/]# kctune filecache_max
Tunable              Value  Expression  Changes
filecache_max  12239650816  Default     Auto

Regards,

Morshed.

[Dennis Handly]

>memory utilization is 93% where file cache is 11.4 GB. what to do?

Why do you think there is anything you need to do?  You have 1.8 GB free.

What problems do you see?

[Santosh Abraham]

The filecache_max is at it's default setting.   Are you running a file-intensive workload ?  

  Note that no matter how high you set filecache_max to, chances are you will end up consuming that much of memory.  In general, most applications do not need to cache so much of their file data.  If you are concerned about memory utilization you can reduce it to a lower value (say 20%).

Generally, in my experience most customers are happy with filecache_max at around 20% or lower