MATLAB: Does the download fail with an error “lost connection to the download server”

MATLAB

I am downloading and partway into the download it fails. The error message states that it has lost its connection to the download server.

Best Answer

Generally this is an issue with firewalls or security software that does not allow the download agent to download zip files. As a workaround, disable your security software or try manually downloading MATLAB without the download agent.

Related Solutions

MATLAB: How to troubleshoot the “lost connection to worker X” parallel error

There are two key causes to this error. The easiest to rule out is whether the worker in question has crashed.

MATLAB Worker Crash

A crashed worker will leave behind a crash dump just like a normal MATLAB. On a cluster this crash dump will be on the compute node hosting that worker.

Determine the location of any crash dumps from https://www.mathworks.com/matlabcentral/answers/100816-how-do-i-locate-the-crash-dump-files-generated-by-matlab

Crash dumps can also be located for non MATLAB Job Scheduler clusters in the following location:

>> c=parcluster()
>> c.JobStorageLocation

In that location look for the Job# folder for the job number which failed and access any Job#.log files.

Once you have the crash dump examine the dump for further information. If the crash was in mex code you wrote then it is worth running that mex code locally to check for issues. Otherwise please contact Technical Support to assist with understanding and troubleshooting your crash

https://www.mathworks.com/support/contact_us.html

Network/Communication Issues

If no crash dumps can be found then network/communication issues are the likely cause. In some situations this can happen when any of the machines are significantly slowed down by resource contention (e.g. memory swapping) this can delay communication signals between workers enough to disrupt the pool.

As well as the node slowdown there is the additional chance of failure from network latency or connection dropping to contend with. At this point try checking the network reliability or consider the step below.

Setting SpmdEnabled to false

An SpmdEnabled pool cannot continue once communication between workers or between workers and client has been lost. If you are using the local scheduler or MATLAB Job Scheduler and only using parfor and parfeval then you are able to instead specify the flag 'SpmdEnabled' 'false'. See the documentation about SpmdEnabled for details- https://www.mathworks.com/help/parallel-computing/parpool.html

A pool with SpmdEnabled set to false is unable to complete spmd statements

With this option the remaining workers will continue to complete the parallel work even after 1 worker has lost connection.

If you need further help and support with dealing with this error please contact

Technical Support