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vSphere 6.0 performance metric limitations in the database (config.vpxd.stats.maxQueryMetrics)

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A change I noticed right away between vSphere 5.5 and vSphere 6.0 is the introduction of a default limiter when it comes to performing database queries for performance metrics.

When querying vCenter 6.0 for performance data, there is a system in place by default that limits the number of entities that are included in a database query. As performance charts in the vSphere Web and C# client depend on this performance data, you may sometimes see an error when attempting to view overview or advanced charts because of this change.

In my case, I am using some custom code to query performance metrics using vSphere APIs and noticed the issue right away, as I was trying to gather a large amount of data.

VMware state that the reason for the change is to protect the vCenter database from receiving intensive or large queries.

If you wish to work around this, or remove the limit, you’ll need to introduce a new key/value pair advanced setting in the advanced settings area for your vCenter server instance. The key should be named “config.vpxd.stats.maxQueryMetrics” (without the quotes) and should have a value set of -1 to disable the limit. This could also be set to a value of 100 for example to limit the entities included in a database query to 100.

A further edit should be made to the web.xml file, however in my case I was not concerned with the limit affecting the client, as I was using the API, and making the first change seemed to do the trick for me.

You can read more about this setting by using this link to the official VMware KB article

How to increase the default exchange 2003 SP2 database store limits

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This applies to Exchange 2003 SP2.

Today I had a call from a client complaining that their e-mail would sporadically stop working every day or two. They said that by restarting the server, they could temporarily fix the problem.

I connected up, and took a look at the server’s event viewer application logs, around about the times that the client complained this last happened, which was around 07h30 in the morning. At 05h00 in the morning, when the exchange database runs some checks, I found the problem. A warning event that complains that the exchange logical database is now over the default size allowed. Logical size being the physical size of the .edb and .stm files, less the logical free space (also known as white space). Anyway the defaults size for the entire database is 18GB (16GB + 2GB). We need to adjust these now, as our combined mailboxes and public folders are over the 18GB size limit, or are quite close to breaching the limit. If they are over, then your exchange database would have already dismounted following the next check at 05h00 in the morning. If they have not passed the 18GB limit, then you will probably just be getting warning events at the moment, and should still increase the size limits to avoid any downtime.

This is how…

Open the registry editor – Start – Run, and type : regedit
Click Ok

Now navigate to (Note that the GUID is a unique string of numbers for each server) :

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\MSExchangeIS\NameOfYourExchangeServer\Private-GUID

Create a new DWORD entry as follows :

Database Size Limit in GB

Right-click and modify the entry once created, and give it a decimal value of anything between 1 and 75 depending on how many GB you want to limit this size to. Make sure you have enough disk space free on the partition your Exchange database is residing, and then enter something higher than 18. For example I used 60 for 60GB.

Modify the exchange 2003 SP2 default database size

Click OK

Now navigate to the next part (This is to modify the public folders database size) :

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\MSExchangeIS\NameOfYourExchangeServer\Public-GUID

Do the same as above, by creating the same DWORD value, and give it a size limit (decimal value) higher than the current public database value. For example I used 15 for 15GB.

Click OK.

Now we need to exit the registry editor, and restart the Exchange Information Store.

Go to start – run, and type : services.msc

Press enter, or click OK.

Navigate to the Exchange Information Store service, and right click it. Select the restart option.

Please note that this will now dismount your store. If your mail store is still online, users will be temporarily disconnected while the store re-mounts itself. Once back online, the database sizes will have increased, and you will get some nice notifications in your application log informing you of the new database sizes.