vor23

@hikinmike thanks for the suggestion; I already made it work for me, and am requesting the change for the benefit of others.

Bryle, no need to re-upload. What I have discovered is that when a problem occurs, if I simply remove the local zip files and do the restore again, the zips are downloaded again from Google Drive, and usually the restore then proceeds without errors. So the problem is in the mechanism that downloads the zip files from Google Drive. Is this mechanism provided by WordPress or by UpdraftPlus?

I made a new backup today (after updating WordPress itself and several plugins), and I got a warning that the plugins zip file was smaller than expected. I checked the zip file, and it was the right size; a test unzip also worked. So I proceeded with the restore, and it went fine. In the Google Drive folder I shared before I put both the screenshot of the warning as well as the log file for the download of the zip file in question. So, not an exact replication of the problem, but the warning shows that something is still not right.

Bryle, thanks for checking. I haven’t replicated the problem yet, but then again, I’ve been doing other work in the past two weeks so I’ve done only one backup or so in the meantime. It usually takes about six backups for the problem to surface. Given that nothing has been actively done to fix the problem, and it has been around for months if not years, I doubt the problem is gone.

Hi @bcrodua,

I have lowered the backup archive split size. I’ve also enabled debug mode, and unchecked the “delete local backup” option. The problem doesn’t happen every single time but instead is sporadic, so I’ll likely have to do several tries before I have another occurrence of the problem. I’ll post here the information I get once that happens.

I’ve put the longer, corrupt zip file on the Google Drive link I provided earlier. Please examine it to see what might be causing the problem. Thanks in advance.

@bcrodua, that might be true if the corrupt zip file were shorter than the one that works. But the fact is that the corrupt zip file is bigger. Let me put it on Google Drive, for you to see what could be causing the zip file to be bigger and failing to unzip.

Bryle, if I download the file directly from my Google Drive, it is not corrupted; if I then upload it to my website using the “Backup/Restore” tab it then works fine: there’s no warning of a different size than expected, and the restore proceeds successfully. Because of this, I think the problem is with WordPress or UpdraftPlus retrieving the file from Google Drive.

Hi @bcrodua

The problem keeps happening, and I may have narrowed it down to something that can be debugged:

https://www.ads-software.com/support/topic/backup-zips-are-sometimes-corrupt-when-retrieved-through-wordpress/

Please take a look. I can provide other examples, and reproduce the problem within a few tries.

As a software developer and Linux administrator, I believe more can be done to improve the reliability of this plugin, even before this particular problem is resolved: one way would be to produce a checksum of the backup zips, so that the integrity of such large files can be verified. Another one is this: since “old” folders are created during restores, a “restore undo” functionality can be created at the folder level (so for plugins, themes, and content–not for the database) by simply removing the restored folders and renaming the “old” folders back to their original name. Additionally, when unzipping a backup during a restore, the system could stop and verify whether the user wants to continue if the unzip throws an error or produces no output. All of these functionalities are feasible and not difficult to implement, while reducing/eliminating the impact of the related problem.

Here are the text files that show the problem:
https://drive.google.com/drive/folders/1FUZRMpZnYssMh4fLTuoomOPFAgaqhlh2?usp=sharing
I can also share the zip files themselves, though they’re around 81 megabytes in size each.