I cannot find anything about how to monitor or at least to view the amount of disk space available and free for use for Universal Messaging.
If I understand the concepts properly, documents can remain on disk a lot more longer than they do remain in memory. Hence it is key to have a look at disk space usage not to be caught out of guards when disk is close to be full.
Can this be monitored by Enterprise Manager?
Are there any IS built-in services to retrieve these kind of information?
On your UM EM, select your realm UM server and go to Status tab. There are stats shown for Memory Usage (M) is that the same you are looking for?
These stats are memory usage and not disk usage: if I have proper understanding of UM behaviour, persistent documents remain both in memory and on disk for some time. However, they’re cleaned out from memory way before they’re cleaned out from disk.
Hence, disk usage can be higher than memory usage and this is why I’m looking for specific disk usage information. Is there any way to get this kind of information?
I went through the docs and found something about EventStore it shows the used space and % Free only relevant for persistent /
mixed channels and also there some configurations for the memory threshold under EventStore see if that helps.
We can also wait to hear from our Product Managers and their comments.
I’ve noticed this as well, however, the %free space is defined as below:
% Free - The amount of free space in the channel store (calculated as (used space -
(total space used by all purged or aged events))
with
Used Space - The amount of space in KB used by the channel on the server (either
memory, or disk for persistent / mixed channels)
What would be interesting is the Total Used Disk Space of all persistent / mixed channels vs the Total Disk Space.
If I understand it well, Total Used Disk Space can be estimated with a complete list of all the Used Space for the persistent / mixed channels. Though the mixed channels Used Space could be both memory and disk (they’re mixed 
).
There would be a way to estimate also the total disk space that could be used by listing all persistent / mixed channels event store size.
However, event store size is defined in “Page Size”, but I cannot see anywhere where this “Page Size” is defined.
So lots of missing information to be able to complete this easily.