Optimal cache memory limit for DNN in shared hosting environments

I installed the free version of Page Blaster this week on my DNN 4.5.5 install. My site is in a shared hosting environment. When installing Page Blaster I kept the default configuration parameters in the PB configuration XML file (i.e. 25MB limit for Memory cache and 100MB limit for disk cahing).

All went well for two days until my hosting company said that (for the first time in over a year of them hosting my DNN site) that my memory usage in the shared environemnt was excessive (accoridng to their email to me: "The site's application will jump to over 200MB in less than 5 minutes"). I reacted to this then by reduicing the PF Memory cache in the configuration file from 25MB to 5MB). As an extra precaution I also deleted 4 DLL files from the DNN bin folder that my install didn't use and then restarted the app by adding an extra blankspace to the web.config file. So far all is fine, no other warnigns from the hostign company since the changes and site is working smoothly. (I confirm as well that I did not install any other DNN modules in the last few days, and that the only 3rd party DNN module on the server is Active Forums v3.7)

My questions are:

• Is there a recommended Page Blaster memory cache limit for DNN sites on shared servers? Is the suggested 25MB limit in the configuration file really best for dedicated servers?
• I kept the memroy cache interval to the default - of 4 hours. If I reduce this can it help?
• Any other suggestions to avodi this sort of warning from my hosting company? (who BTW are a DNN benefactor, platinum I think)

I am curious to know!

Thanks,

eoghano

Hi eoghano,

What you experienced is normal.  A DNN website usually takes about 160-200 MB of memory, so adding PageBlaster probably pushed you over their threshold if it was at 200.

The default setting of 25MB is more or less optimal for any environment just because that size will store a lot of pages in the memory cache. The setting was put there to limit the memory use in shared hosting environments, but no site should really need more than that.

Decreasing the size will not be a problem on small sites either though. At 5 MB you are still going to be able to cache about 1000 pages in memory on average.  The amount of time can be increased also. 4 hours is on the low end of how long you may want to cache a page, but if you are getting decent traffic then the 4 hour limit may not ever be reached since it is a sliding expiration window. In other words, as long as the page gets called again in that 4 hour window, then it will not be removed from memory.

The other nice thing about PageBlaster is that the whole page also gets cached to disk, so if you are using memory caching, and a page does happen to expire or the application restarts then the next page request can be pulled from disk just like a static html file. After the page is pulled from disk it is put back in memory for the next request, so the disk backup even if you are using a low threshold for memory will provide great performance too.

You may want to tell your hosting company why your memory consumption changed and enquire as to what your threshold is.  200 MB is about as small as should be allowed for a DNN site.