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Copying Video Recordings (including some that are In-Progress)

justbackmeup :

Jun 07, 2018

I want to use Bvckup to copy video recordings from one location to another. However, recordings will often be occurring at the same time that a Bvckup operation is happening, and the recordings-in-progress are not named any differently from the final file (so there's no way to exclude the in-process ones) -- the only difference is that file size keeps growing until the recording completes. The copying will be occurring on the same drive (ie, from one folder to another folder on the same drive).  

I probably want to run Bvckup on a pretty regular schedule (every 5-10 minutes?) because the recording start/stop times may vary (though recordings themselves will usually be around 50 minutes long, so most of the time there will be nothing new to copy). The locations are on a NAS, so realtime monitoring might not be reliable, thus something like 10 minute intervals is probably the way to go.

Any thoughts or recommendations on how to do this most efficiently? I'd like to capitalize on as many of the speed/efficiency benefits of Bvckup as possible. Is there any way to have Bvckup wait until a file is done recording before copying it and/or will delta copying come into play at all here? I'm guessing not (regarding delta copying) because the modified time will keep updating until the file is done recording.

Thanks for any thoughts, recommendations, etc.!

Alex Pankratov :

Jun 12, 2018

There's no reliable way to detect "live" files except for checking if the size of a file is changing. File timestamps are not getting changed.

This is something that *can* be done, e.g. by checking that the file size hasn't changed between when it was picked up during the scanning phase and the moment when the program gets to actually copying it. So we can have an option to suppress copying in this case (and possibly log an error?).

In terms of delta copying - it will be used and the file *will* be updated on every run, because even if its timetamps won't change, its size will. Delta copying kicks in whenever the _backup_ copy matches the block-hash file saved on the last run, and in your case it will match. So what you are looking at is the program going through the previously backed up part of a live file (reading it in full) and then resume copying from the point where it stopped last time. The waste here is the extraneous reading of the leading part of the file on every run, but depending on your storage device and file cache size it may not be that big of a deal.

justbackmeup :

Jun 12, 2018

There's no reliable way to detect "live" files except for checking if the size of a file is changing. File timestamps are not getting changed.

In this particular case the modified time will keep updating (every few seconds?) until the file is done recording, so does that change any of what you're indicating above?

The extraneous reading of the leading part of the file on every run might not be a huge deal, but if there's a way to prevent copying until the file is done that's probably best. Since the modified time will get updated in near-real-time by the software writing the file, is there an existing way that I can tell Bvckup to only look at files whose modified time is 30 seconds ago or older (or something like that)?

Ah, I believe I've answered my own question! :) I just did some looking at Filters in the software and in the forum. I currently have an Include filter for Files of:
*TESTING-NAME*

And so I added an Exclude filter for all files (using just * for Matching), and set "On or after" to be "now - 30 seconds", and made sure to make this rule Final by moving it to the top (I missed this on my first try). In my initial testing this seems to work for Excluding files that were modified in the past 30 seconds, but then picking up those files on the next run. I think that should achieve what I want and avoid unnecessary copying.

Let me know if you notice anything I'm missing!

Alex Pankratov :

Jun 12, 2018

In this particular case the modified time will keep updating (every few seconds?) until the file is done recording


Are you sure? Last-modified time is usually updated when the file is closed, not when a write occurs. So unless recording software does open-write-close for every write, you won't see last-modified time change until recording is done.

justbackmeup :

Jun 12, 2018

Yup, I can watch it update in real-time. This is surveillance software on my Synology NAS, so perhaps that gives it abilities in this regard that are unusual (because maybe the vendor can integrate it tightly into the system)?

In theory I could write a script to do the copies all on the NAS itself and not be moving data back and forth over the network, but the connection is local/fast and it's just so much easier to work with Bvckup for this sort of thing. :)

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