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Akeeba Backup for WordPress

#33357 – Unable to complete

Posted in ‘Akeeba Backup for WordPress’
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Tuesday, 07 July 2020 04:50 CDT
milohunt

I have a rather large WP website - 6GB (mostly because of images), my backup is stuck at 74% for an hour now. Server response is above 100s and here are some stats:

Physical Memory Usage: 6GB / 6GB - akeeba using all (100%)
I/O Usage: 5.74 GB / 6 GB (95.6%)
CPU Usage: 23 / 100 (23%)
Number Of Processes: 3 / 100 (3%)
Entry Processes: 2 / 80 (2.5%)

 

What do I do?

Thanks

EDIT: Akeeba finished, with error, LOG file is zipped but I can't attach it here, how do I send it to support?

Analysis says:

ALICE finished its log analysis. A total of 0 different checks were executed.

 

 

 

 

 

 

Custom Fields

WordPress version (in x.y.z format) 5.4.2
PHP version (in x.y.z format) 7.3
Akeeba Backup version (x.y.z format) 7.2.0.1
Tuesday, 07 July 2020 06:05 CDT
milohunt

Log is attached

Tuesday, 07 July 2020 08:06 CDT
nicholas

You would need to contact your host.

Based on what you tell me, your host is using up as much physical memory as the size of your site's files. However, Akeeba Backup runs in small and discrete steps, each one backing up a few files. The way our algorithm works, its maximum physical memory use is under 32MB (typically well under 20MB).

I do know why your host may end up using up all of its physical memory. It is probably using CloudLinux which has a major bug that's confirmed since at least 7 years ago and marked as something which won't be fixed. A normal server makes use of the free memory (memory that applications don't use) for disk caching. When applications need memory and there's no more free memory the Operating System will take memory from the disk cache and assign it to the application. There's no latency between memory pressure and taking away memory from the disk cache.

CloudLinux has a bug which prevents it from doing that. Once the memory is used for disk caching it will take a long time, in the order of several minutes, before it decides it should deallocate memory from the disk cache. When you are running a backup – even when simply using tar from the command line – this bug will cause physical memory exhaustion.

There is no solution to this problem. It's a problem inherent to the design of CloudLinux.

A workaround is to exclude the big images folders from your main backup profile. Then create 2-3 backup profiles with their types set to Files Only, each one backing up a portion of the images. Automating these backups would require scheduling them so there's an at least 30' gap between one backup finishing and another starting up.

Again, this is a problem with the design of CloudLinux, nothing we can do about it. Because it's a problem at the OS level you won't be able to use any other backup solution either, be it a plugin or even command line tools.

If you're wondering, yes, it took me several days of head scratching to understand this problem when I first encountered it circa 2014. It is a very rare problem but it can and does happen with larger sites. IMHO a site as big as yours shouldn't be on a shared host. If you are NOT on a shared host then your hosting company shouldn't be using CloudLinux for a managed server.



Nicholas K. Dionysopoulos

Lead Developer and Director



🇬🇷Greek: native

🇬🇧English: excellent

🇫🇷French: basic



Please keep in mind my timezone and cultural differences when reading my replies. Thank you!



Tuesday, 07 July 2020 11:52 CDT
milohunt

Thanks Nicholas,

Yes, my host is using cloudlinux, I've sent them an email and will share the response with you once they reply. Thank you

Tuesday, 07 July 2020 23:29 CDT
nicholas

You're welcome!



Nicholas K. Dionysopoulos

Lead Developer and Director



🇬🇷Greek: native

🇬🇧English: excellent

🇫🇷French: basic



Please keep in mind my timezone and cultural differences when reading my replies. Thank you!



Thursday, 09 July 2020 06:21 CDT
milohunt

Hey, 

it looks like I will have to change the host or get a VPS for this site, meantime I'd like to disable automatic scheduled backups, but I can't seem to find the disable function, can you please help?

Thanks

Thursday, 09 July 2020 06:42 CDT
nicholas

Remember that you do not schedule backups from the plugin itself. You have created a CRON job in your hosting control panel. This is where you need to look and disable or delete the CRON job which runs the scheduled backup.



Nicholas K. Dionysopoulos

Lead Developer and Director



🇬🇷Greek: native

🇬🇧English: excellent

🇫🇷French: basic



Please keep in mind my timezone and cultural differences when reading my replies. Thank you!



Saturday, 08 August 2020 17:17 CDT
system
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