backup zips are sometimes corrupt when retrieved through WordPress

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.

Hi,

Thanks for sending the log.

Do you still get the same corrupted files if you download it directly from your Google Drive? Then just upload it to your website in the UpdraftPlus “Backup/Restore” tab?

Regards,
Bryle

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,

I believe the connection is being cut-off by your server or by a firewall. Try checking with your host too. I’ve done some tests on my end using our UpdraftClone server and it works fine for me.

Regards,
Bryle

@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.

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.

Hi @vor23,

Could you try to reduce the backup archive split size? To do this, open the ‘expert settings’ section of the UpdraftPlus Settings tab, and find the ‘split backups every’ option. Set this to 25Mb save your settings and run a new process.

Then try to download a copy of the backup file again, do you still get the same issue?

Regards,
Bryle

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.

Hi,

Just checking back if you are still experiencing the same issue?

Regards,
Bryle

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.

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.

Hi,

Can you re-upload the component that is having issues? It appears that the plugins.zip transfer has failed partway.

Regards,
Bryle

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?

Hi,

Apologies for the delay.

Thanks for the information.

I will ask our team to investigate on the issue.

Regards,
Bryle

Hi. i am experiencing the same issue. Latest version of WP (5.5.3) and updraft uploading to Google Drive (only one site backed up).

All backup uploads to Google are ok and can be opened. It is only when I try to restore a backup that the download from Google to the server gets corrupted. Same issue. Corrupt downloads are always bigger than expected.

example message:

 Warnings:

    File (backup_2020-11-03-1342_xxxxx_8bf893b5b2fa-plugins.zip) was found, but has a different size (31990128) from what was expected (26480829) - it may be corrupt.
    File (backup_2020-11-03-1342_xxxxx_8bf893b5b2fa-plugins2.zip) was found, but has a different size (7562784) from what was expected (5465631) - it may be corrupt.
    File (backup_2020-11-03-1342_xxxxx_8bf893b5b2fa-themes.zip) was found, but has a different size (5430356) from what was expected (4812331) - it may be corrupt.

I have reduced the archive split size to 25Mb but seems to make no difference – if anything it has made it worse. At default size of 400, only the biggest file (30mb) was corrupted, now the same split archive and smaller ones will report as corrupt.

If I download the backup files to my local computer after download by Updraft, then, from the examples above, 2 out of 3 files cannot be opened.

Please can you report on the prgress to fix this issue please.

thanks, Colin