WebDAV backups do not finish successfully

Hello,

We keep our website backups on a separate cloud space for redundancy. Our updraft-generated backups (using the paid version) have been saved to our OneDrive cloud for years, but due to an increase in our OneDrive security, we have decided to migrate our backups to a dedicated WebDAV enabled cloud.

We tested the solution to be functional on the Koofr cloud by backing up only the WordPress database using our WebDAV credentials, and it worked perfect. We then purchased 1 TB of WebDAV-enabled, lifetime cloud storage space, and configured UpdraftPlus to interface with our new cloud storage. It is important to note that Koofr has no file size or I/O limits per their sales material.

At first glance all seemed to work fine. When looking at the storage area, I could see that the files were being created realtime and in the correct directory on the cloud as intended, however as time went by I realized that non-database backups are taking an extended period of time (overnight) and never ever completing. Only small files appear to complete and large files are continually retrying.

We are using the latest paid version of the UpdraftPlus plugin with all the add-ons. We are using WordPress 6.0.2 with the following configuration which have been confirmed through more than one tool. It may be important to mention that we are on PHP 7.4 and cannot upgrade to 8.0 or 8.1 as our theme cannot support versions beyond 7.4 at the moment:

php_value max_execution_time 600
php_value max_input_vars 3000
php_value max_input_time 1000
php_value memory_limit 2048M
php_value post_max_size 128M
php_value upload_max_filesize 128M

When the website produces a LOCAL backup it only takes 22 seconds for a complete and successful backup as we are on a high-end dedicated hosting server with SSD storage on GoDaddy.

While we were using OneDrive with max execution time of 300 everything worked fine since year 2020, but using WebDAV we cannot get a successful backup even though files are in fact being created on the desired cloud volume. They simply never finish without errors. It keeps delaying and restarting until it gives up over hours.

We also tried file sizes 400, 300, 200, and 100 MB all without success. Database backup alone finishes just fine (we only tried with a 400 MB chunk size).

I would be happy to email you the generated log file if you would provide an email address or a secure FTP box to send it to.

Since we tested this configuration to work before we purchased non-refundable lifetime cloud space from a reputable storage provider offering WebDAV, and we can successfully access the volume and drop files in it using WebDAV, we really need to get our issue resolved, and your assistance would be highly appreciated.