Gmvault VS CloudEndure

I use GMvault for doing this and I'm quite happy with it. Unfortunately, it's not actively maintained anymore and out of the box, it doesn't work properly thanks to some annoying changes that Google has made to Oauth, but fortunately, there's plenty of documentation on GitHub for how to fix it. I have GMvault set up to run nightly using a cron job on my NAS. Source: 12 months ago

With gmvault you can download and sync. http://gmvault.org/ it saves in .eml format, I assume you could use a locally installed web mailer for accessing the emails? Source: about 1 year ago

I used this until I didn't need it any more, worked perfectly for a long time: http://gmvault.org/. Source: about 1 year ago

I recommend to look in gmvault http://gmvault.org/ . Source: almost 2 years ago

It's a good idea to use something like gmvault [0] to ensure you have regular downloads of your mail corpus locally. [0] http://gmvault.org/. - Source: Hacker News / about 2 years ago

You can use cloudendure.com, bought some time ago by AWS to make it's technology free for any_to_AWS move, agent based that will copy bit-by-bit and you can test vm on the other side before final cut on source side... Source: over 2 years ago

That being said, I'd still vote for the rearchitecing part, at least to the level what you were describing. If you do decide to lift-and-shift tho, we just completed a big migration with CloudEndure and I can recommend it. Source: about 3 years ago