The only way to speed synchronization up seems to be the set the ignore_regexes
options to exclude large folders that won't be edited (e.g. libary folders).
You can exclude folders by setting something like this:
"ignore_regexes": [
/* leave default rules*/
"/var/www/someFolderLike/Lib/Zend/",
"/var/www/anotherFolder/",
]
Folder paths might need to be relative to your server root path.