Short time outs are to be expected when initiating and commiting the snapshot.

The larger delta file is the longer the time out will be.

Snapshots should only be used for a very short time.

e.g

Backing the parent files and config and then commit the snapshot.

You do not want them to grow, they will significantly degrade performance.

Snapshots are not backups, they are deltas of disk change and will significantly increase the disk I/O load of the storage subsystem.

The loss of connectivity is due to the temp delta file commit time. When the snapshot is commited it creates a temp disk and mem file that holds all the changes since the delta vmdk started writing out to the parent vmdk. When the temp files are commited the VM will not respond until it's complete.

You are correct in adding memory to the COS resource pool it will help speed up the process and reduce the negative impact.