Test your iCloud

Cirrus provides a small, standardised test involving the copying of a 1 MB file from local storage (in ~/Library/Preferences/co.eclecticlight.Cirrus.data) to your iCloud Drive. This is ideal for observing the transactions which take place in the iCloud subsystems and services, and should help diagnose problems.

To run the test, ensure that you can see a Finder window in which the iCloud progress icon will be visible. Then press ⌘ 1 to trigger the Test Upload command in the Window menu, or click on the Copy to iCloud button in any document window, and watch that progress icon.

Cirrus then creates a 1 MB test file consisting of the byte 0x88 repeated throughout and saves it to ~/Library/Preferences/co.eclecticlight.Cirrus.data. The app next checks to see if there is already a test file in your iCloud Drive, at ~/Library/Mobile Documents/com~apple~CloudDocs/co.eclecticlight.Cirrus.data. If there is, that is deleted.

Cirrus then tries to copy the test file from ~/Library/Preferences/co.eclecticlight.Cirrus.data to ~/Library/Mobile Documents/com~apple~CloudDocs/co.eclecticlight.Cirrus.data, which should then appear at the top level of your iCloud Drive folder.

Observe when iCloud’s progress icon completes and disappears, marking the end of the copying process. To browse the log for that period, open a new log browser window and use those times as the basis for the times set in the Start and End boxes in that window. If you make the interval between Start and End too short, less than about 20 seconds, some log entries may be omitted.

Once copying is complete, you can press ⌘ 2 for the Clean up Test command, or click on the Clean up button, which removes the two copies of the test file.

Once the test copy is finished and you are happy with the Start and End times, and ensuring the the real clock time is now later than the End time, click on the Get log button in your log browser window to view the log during the copying process.

You can also perform a manual test, in which you drag-copy a file to your iCloud Drive, and set the Start and End time according to your Mac’s clock. You can use a similar technique to assess log entries when saving a document from an app to iCloud, or for any other function that you wish, although you will have to enter Start and End times manually for those.

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