Gaps in saved voice mail

Discussion in '3CX Phone System - General' started by imabev, Jul 6, 2016.

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  1. imabev

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    We have been experiencing a problem with saved voice mails. The sound gets saved out of order with gaps where the out of order sound should have been. I have uploaded a clip of an example to clyp.it https://clyp.it/ndk2xlzs (it's safe!).

    You can hear in the recording that where the gap is actually gets moved up in the clip. Assume points in the vm are numbered 1-5. On playback you hear you first 5 seconds almost on top of each other (then a gap where the second half of the 5 seconds was supposed to be) then resumes normal playback.

    It has not been reproducible as of yet. My best estimation is that it happens about 15% of the time.

    Here's my thoughts - don't let this get you off the track because it's just observations at this point. I don't think it's a qos or network congestion issue. I have never heard this or received reports from a live phone call. This particular email was recorded in the evening where there is virtually no traffic. When these gaps happen (from the 10's of vms I have heard) it appears that the gap occurs in the beginning of the vm.

    Has anyone heard this before? The 3cx server is running on hyper-v server 2012R2 with 4 virtual processors and 8GB of RAM.
     
  2. NickD_3CX

    NickD_3CX Support Team
    Staff Member 3CX Support

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    I have seen similar cases caused by only 2 reasons in the past:
    - Either for some reason that is indeed how the audio was received on the NIC of the 3CX Server, which could mean either Jitter on the network or the VM loosing track of time (time slide), so as this is a Hyper-V make sure you have integration services installed.
    http://www.3cx.com/docs/installing-microsoft-hyper-v/
    or
    - The read/write speed dips at that point so that 3CX Server cannot write to the disk in time. Because of the nature or PBX, VMails and Call Recordings are not buffered, they are written directly to the disk.
     
  3. imabev

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    Thanks, Nick. My best guess is it's some kind of delayed disk write. It's only a guess at this point - I would think I would have heard myself or some reports that says this type of behavior happens on a live call.

    I have verified that the hyper-v server has integration services and is using the VM IC Time sync clock.

    Have you ever seen any issues with virtual machine queuing issues on the hyper v network adapter? We've had some issues with that in the past (other issues).

    My only other guess is to move the 3cx server to another host. It shares a host with a SQL server which could be delaying the writes.
     
  4. NickD_3CX

    NickD_3CX Support Team
    Staff Member 3CX Support

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    Sorry, nothing rings a bell, someones else might have though....
     
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