Resolved Plesk FTP Backup Issue

[easyware]

Hi everyone, this is getting some kind of annoying and I am trying to figure out what is happening.

PROBLEM
Every now and then the scheduled (every night) Plesk backup on my local FTP fails, sometimes because of connection issues (italian "fast" internet connection yay!), sometimes for Plesk issues, .. but eventually the backup gets done.
My setup is for incremental backup and a weekly full backup, obviously the issue is on the full backup (chunks of 2GB archives).
This time it is now 8 days of errors, it is starting to get dangerous.

QUESTION
What does Plesk need to correctly perform the full backup task? How does the task works?
Is it done locally and then transferred via FTP? How much free disk space do I need on the server?

ERRORS AND LOGS
Here are some Plesk generated e-mail to notify the error, sometimes they just say "error" with no dump (in that case on Plesk I just see "Backup {DATE} has not been created".

Backup task finished on host {HOSTURL}

Creation date is: 2021-Jul-15 01:40:06
Created by: Plesk administrator (type=server, guid=d180640c-e4b6-4a03-a1c9-dc913605933b)
Created for: Server (type=server, id=1)
Task status is: error (see details in the attached file)

Dump full name is:

Attached is one of the few dumps, in this case the backup has been partially done (I see an exclamation mark on the left in the FTP backup list).

Thanks to everyone will try to help..

 

[weltonw]

It looks like a memory issue. What is the resource usage like during the backups?

 

[easyware]

Thanks John for your insight.

Yeah, that's why I am trying to figure out how much free space do I need to live quietly..
My full backups are about 40GB, do I need 40GB of free space?
If my backup is in 2GB chunks, do I need still 40GB of free space?

As far as the process goes sometimes (not every time) I receive disk usage notifications when I wake up the next morning, but looking at the values seems to be that there still is free space, next to it a "disk space has been freed up" notification.

Here they are, for reference..

Disk space usage has reached the threshold - 01:57 AM

Disk space usage has reached the specified threshold on host:
Device name: /dev/mapper/vg01-root
Mount point: /
Capacity: 124233728 kilobytes
Used disk space: 109028100 kilobytes
Maximum number of files: 66774320
Current number of files: 5800096

The problem was discovered on Jul 16, 2021 01:57 AM.

Disk space has been freed up - 08:55 AM

Disk space has been successfully freed up on host:
Device name: /dev/mapper/vg01-root
Mount point: /
Capacity: 124233728 kilobytes
Used disk space: 105711472 kilobytes
Maximum number of files: 80041728
Current number of files: 5803775

The problem has been resolved on Jul 16, 2021 08:55 AM.

 

[weltonw]

The best way for you to answer that question is to measure it. Given, I'm not actually familiar with how Plesk takes it's backups, but there might be something in the docs or someone else can chip in.

From what I'm seeing in our data, it looks to be subscription-based.

 

[easyware]

If it can help the backup process I am using is the "Server-wide Backup".

 

[easyware]

New errors (migration.result attached)

Backup task finished on host

Creation date is: 2021-Jul-21 01:38:36
Created by: Plesk administrator (type=server, guid=d180640c-e4b6-4a03-a1c9-dc913605933b)
Created for: Server (type=server, id=1)
Task status is: warnings (see details in the attached file)

Dump full name is: backup_2107210138.tar

Now, this is new..
pmm-ras failed (Error code = 1): Repository error: Failed to read backup backup_2107200139.tar: Import error: Unable to find archive metadata. The archive is not valid Plesk backup or has been created in an unsupported Plesk version

I am about to upgrade the disk space (this is a VPS), I just hope I am not throwing money away..

 

[mow]

Thanks John for your insight.

Yeah, that's why I am trying to figure out how much free space do I need to live quietly..
My full backups are about 40GB, do I need 40GB of free space?

yes

If my backup is in 2GB chunks, do I need still 40GB of free space?

yes (due to the way plesk assembles the backup files - it first creates several .tar.gz for webspace, mail and database, then pipes them into tar again which creates the uploaded file(s) on the fly.)

As far as the process goes sometimes (not every time) I receive disk usage notifications when I wake up the next morning, but looking at the values seems to be that there still is free space, next to it a "disk space has been freed up" notification.

The message from server monitoring only tells you when the disk usage passes the threshold in either direction. It does not tell how disk usage proceeds after that. That the message about freed space shows up almost seven hours later is some indication that it is still filling up, and eventually the backup aborts and releases the space.

 

[easyware]

Thanks a lot Mow, this is the answer I needed!

 

[easyware]

UPDATE - I managed to free some space up on my VPS, tonight after almost 20 days the backup has successfully be done.
So I can confirm what I thought, just as Mow confirmed.

Thanks everyone, greetings from Italy
(is there any way to mark this a "SOLVED"?)