timestamps not being preserved

[Andrew Yung]

Hi all,

I am using Globus for the first time to transfer files from my Almalinux 9 computer to a remote endpoint (UBC ARC Chinook).  I want to preserve the original modification times of my files, so I tried to specify that particular option for the transfer task.  However, this feature does not seem to work - the timestamps of the copied files are the transfer timestamp.

I have tried this both on the Globus website as well as the Globus CLI using the --preserve-mtime option for the "globus transfer" command.

Could it be that the destination endpoint doesn't support preservation of file times?

Cheers,

Andrew

[Karl Kornel]

Hi Andrew,

A quick Google search tells me that Chinook is an object storage, which uses the same protocol that Amazon S3 uses to talk to the world.  Indeed, S3’s last-modified date is different from what you might expect[0].

Globus’ documentation includes a note on how it handles last-modified times with S3[1], but there’s one thing it does not make clear: The docs do say that last-modified times are restored when files are transferred out of Amazon S3.  But the docs do not say anything about the last-modified times displayed in file listings.

I just did a test: I transferred a file from macOS, to Amazon S3, and back to macOS.  “Preserve source file modification times” was on for both transfers.  The Globus web app did not show the correct last-modified time (it showed the time the file was uploaded), but the last-modified time was correct when I transferred the file out of S3.

So, I’ve got a few suggestions for you:

• Try a test transfer out of Chinook, and see if the last-modified times are correct.

• Reach out to the ARC folks, and ask them to update their documentation to mention how last-modified times are handled.

• Open a ticket to Globus Support, asking for an enhancement request: The File Manager should show the ‘correct’ last-modified time, if possible.

Good luck!

~ Karl

[0]: https://stackoverflow.com/questions/75530858/what-is-the-actual-meaning-of-the-aws-s3-last-modified-date-attribute

[1]: https://docs.globus.org/premium-storage-connectors/v5.4/aws-s3/#aws_s3_storage_connector_modification_times_note

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[Andrew Yung]

Thanks so much for the advice!   The behaviour on my setup is exactly as you said - I do recover my file modification date when I copy it back to my original source.

Wow, I would have never been able to figure that out on my own - many thanks!

-andrew