What is the normal memory usage for PHD?

Q&A ForumCategory: QuestionsWhat is the normal memory usage for PHD?
Guest asked 5 years ago

What is the normal memory usage for a PHD server?  I have about 37,000 tags and about 10 active users?

1 Answers
Jason Baum answered 5 years ago

In small systems (~1000 tags), with few users, PHD should use less than 1 GB of RAM
In very large systems (>200,000 tags) with many users, PHD can use as much as 16-20 GB of RAM (*if there are no issues)
The majority of systems should have about 8 GB dedicated to PHD.
Here are some recommendations for minimizing RAM usage and maximizing the speed of the system:

  1. If you have a large system, move the PHD SQL Server (Used for configuration and not data) to a different machine.  SQL Server is notorious for gobbling up RAM.  Whenever you make a query, like, “Give me the complete list of all the data in a particular table”, it will hold the results of that query in memory just in case someone else makes the same request in the future.  So the data will be sitting in RAM for a long time, often for no reason, while your server may be suffering for lack of memory.  
  2. Clean up the tags in your system.  Sometimes PHD can start using too much RAM if it is trying to collect tags that no longer exist in the source system.  Delete them, set them to inactive, assign them to a non-collecting interface (RDI), or, if you know how, turn them into manual input tags in the database.  
  3. Ensure that PHD has file system rights to the Archive file location.  There is a bug in PHD that if the security settings are not correct, PHD will work, but keep eating RAM until it eventually crashes and has to be rebooted.
  4. Check and see how many users are accessing the system.  This can be determined (At least as far as PHD believes to be true) by clicking start, All Programs, Uniformance, PHD Server, API Server Information (And then, subsequently, Remote API Server Information).  When you click this, nothing will appear to happen.  If you look closely at the icons on the bottom right of the screen, you will see one that looks like a bolt with a couple of nuts screwed onto it.  Right-click on this and highlight, System Info.  You will see a listing of statistics including “Peak Connections”.  This is the number of users using the system at once.  Often this is incorrect and you will see a number unreasonably large, like 100, for example.  This is a bug where PHD is miscounting the number of users, or where users open connections and they don’t close.  To temporarily fix this, open regedit, and navigate to HKEY_LOCAL_MACHINE, SYSTEM, CurrentControlSet, services, APIServer (Or RAPIServer), Parameters and change MaxClientLinks from 100 to something like 2000.  Meanwhile, call technical support and investigatge further.  
  5. Review the PHD log files to try to determine why the system is using too much RAM.  Often there are errors that cause this.  The log files may be the key to figuring this out.
  6. Perform more advanced analysis of the RDI Servers, RDI’s, and tags to try to figure out what is wrong.
  7. Call Process Wise at 713-498-9718 and we will take a look for you!  We’ll get it fixed!

 Good luck my friend!

Your Answer

8 + 2 =