Streaming MoH can negatively impact the performance of the PBX due to bandwidth usage or transcoding issues. Multiple callers placed on hold will be connecting to the same stream and each streaming class should be streamed only once at any given time. If multiple streams are created, it is possible for them to be active at the same time. PBX requires that the stream be in ULAW format, so calls already using this codec will be able to listen to the stream without any transcoding. A call that is using a different codec, such as G.722, would force the stream to be transcoded for the caller to hear it. This places a processing load on the PBX and may require additional licenses for the concurrent caller if using a licensed codec. It may be beneficial to avoid streaming MoH for system performance issues. Unless you are streaming audio on your private LAN, the streaming audio will be using the same bandwidth that you need to support incoming and outgoing calls. Anything streamed over 24k is a waste of bandwidth.
Incorrect streaminig sources or settings in the MoH custom application can cause increased warning messages in asterisk CLI as well as in the full log. Messages have a format similar to this one
[2017-10-19 12:10:42] WARNING: res_musiconhold.c:719 monmp3thread: poll() failed: Interrupted system call
Removing streams with invalid URLs, IPs pointing to un-existent resourece will stop these messages from appearing and filling btoh CLI and full log.