Tuesday, March 30, 2021

ExpanDrive and File Provider Framework

Jason Snell:

Long-time Mac storage utility maker ExpanDrive has launched StrongSync, a $50 utility that… sort of does what ExpanDrive already does? Like its big brother, StrongSync allows you to view cloud storage services as if they were hard drives mounted on your Mac.


For storage providers the alternative to using kernel extensions is macOS Big Sur’s File Provider framework. This framework basically allows third-party apps to provide a bridge between the Mac’s filesystem and their cloud-storage providers of choice.


What this means for you: files get downloaded and open when you need them. They don't suck up any free space while not in use. It is fast as if it was local, because it's all on your SSD - not network drive or kernel extension. Strongsync support Sharepoint, OneDrive for Business, Google Drive and Google Workspace, Box with more clouds (Dropbox!) coming soon.

There’s also an S3 Pro app.


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I couldn't get ExpanDrive to work on my new MBA M1 so I contacted support and guess what: they don't support Apple Silicon for ExpanDrive.

Here's a fun exercise: try to find where on their homepage it says that M1 Macs are not supported.

@Adrian I wonder what the limitation is there, since it does work with Big Sur’s kernel extension changes. I guess that’s why even at the top of the ExpanDrive product page it tells you that StrongSync works with the M1.

Adrian - still working on it. With M1 you need to reboot into recovery mode in order to enable any third party kernel extension, and we're trying to sort through that still. Ultimately Strongsync and File Providers are the path forward and we're providing very recent ExpanDrive customers a free license for Strongsync if they're interested.

Geez, just republish their marketing materials, eh? "It is fast as if it was local, because it's all on your SSD" This is a load... Access Dropbox right from your SSD? Are we forgetting how this all works?

Not exactly "as if they were hard drives on your Mac" since they ONLY show up in finder and NOT on the filesystem tree at all.

@R My understanding is that the files really do get stored on the SSD (unlike, say, with SMB) and that they do show up in the filesystem and so can be accessed from other apps.

@ Michael: I don't see how they can _both_ claim "files get downloaded and open when you need them. They don't suck up any free space while not in use" _and_ "It is fast as if it was local, because it's all on your SSD - not network drive or kernel extension".

If they get downloaded when you need them, they're not "as fast as local".

It's presumably a network drive with a local cache.

@R all of the files actually are on your SSD in ~/Library/CloudStorage - they are actual files, unlike VFS placeholders like with ExpanDrive

@Sören I think it’s basically like iCloud Drive, which can pre-download files so you almost never have to wait, yet if your drive is getting full it will automatically evict stuff that hasn’t been accessed recently. In other words, more like Dropbox, which people don’t generally think of as a network drive with a cache.

@ Michael: sure, but I think that makes "They don't suck up any free space while not in use" rather misleading. They absolutely take up space. macOS and/or StrongSync may just be smart enough to shove it aside when you need it for something else. (And if it's anything like purgeable storage in its early days, hoo boy.)

@Sören Since it is managed by APFS they won't actually count it against free space. It's not unlike files that have been deleted but their data still lives in the tree marked as free space. They have a new grey zone where they can unlink data on demand at no cost.

I have actually tested StrongSync against a WedDAV server.
It's essentially using a new File Provider API that was supposed to come out in 10.15 but was dropped during the beta cycle.
My understanding is the API is still unsupported and Apple aren't providing any code examples ate this point.
In testing, when you mount a remote server, you can see all the files and directories and if you "Get info" on any of them, it shows the size they will take up on disk followed by "zero bytes on disk"
Once you interact with them, they download and if the then "Get info", both figures are the same.
At that point, even Quicklook works as files are local. At any time, you can right click and select "Remove Download"
Interesting point, Quicklook will not initiate a download, it simply won't work.
Once you double click, quicklook works as expected.
Supposedly, there is not file pinning yet, but since using Apple's API, it can evict downloaded files to make space when Filesystem is low. There is no control of this - just like iCloud.

As of October 2021 I'd recommend a whole lot of caution looking at StrongSync. I've ended up having to do a clean install of MacOS because it send the Finder into a full time spinning beachball and lost files in the process of it not syncing files.

It seems very much alpha even though they took $220 off me for the privilege of losing my files and doing a clean install.

be warned!

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