I am using Varnish cache on Magento 2.1, and I need to disable the cache for upgrading purpose.
I go to System > Tools > Cache Management, and select all the cache types, and choose "disable" and submit.
But I this error error:
Deployment config file env.php is not writable.
I tried to chmod app/etc/env.php and app/etc/config.php to writable (777), but still can't disable the cache.
Any idea why this is happening?