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Backup fails after upgrade to 6.6.1

Freddeco
Aspirant

Backup fails after upgrade to 6.6.1

Hi,
 
I have been running a 2 disk 2TB mirror in xraid readynas with full backup to external hdd once a week without any issues.
I have about 228GB of data and 30GB of snapshot. not a lot.
 
After upgrading to version 6.1.1 the backup terminates with a disk full error. Its a 2TB external HDD connected to the nas via the front usb.
 
The disk was in ntfs and i have tried reformating in NTFS, FAT, ext3 and ext4 but still no sucess the backups fails with a disk full error message. i tried formating the external hdd on a PC with a 4k allocation unit size in FAT but the NAS does not recognise the disk. 
I also recreated the backup function (with the option delete all files on the disk) no sucess. 
 
any idea.
 
regards,
Frederic 

Model: RN31211D|ReadyNAS 300 Series 2- Bay
Message 1 of 13

Accepted Solutions
jak0lantash
Mentor

Re: Backup fails after upgrade to 6.6.1

The point is not "how many snapshots" but "is it transferring snapshots". Did you try @StephenB suggestions?
Snapshots are at block level, understand that they contain only the blocks that are different from a reference, which makes them very efficient is used space.
Traditional backups, such as what you're using, occurs at file level. It doesn't have a clue that it's a snapshot, it only considers the files it sees - the full files - the files reconstructed with the blocks in the snapshot merged with the reference(s) - the files like you would see if you were to browse the share.
If the backup tries to transfer a single snapshot, it would require the whole file size, two snapshots, twice. If you have a share with two empty snapshots and transfer the data and the snapshots, it requires THREE times the space.
In FAT, there are other limitations, like the maximum size of a file, which is much lower than the maximum file size on BTRFS. If you were to try transfer a file too big for FAT, it would fail.

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Message 12 of 13

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Retired_Member
Not applicable

Re: Backup fails after upgrade to 6.6.1

If antivirus service is still enabled, please disable, reboot NAS and try again.

Message 2 of 13
Freddeco
Aspirant

Re: Backup fails after upgrade to 6.6.1

already disable

Message 3 of 13
StephenB
Guru

Re: Backup fails after upgrade to 6.6.1

Did you try turning off "snapshot access" on all the shares? This won't delete the snapshots, but it should ensure that you aren't backing them up.

 

Note that the 30 GB used for snapshots is the incremental space needed to store the snapshot.  When you back up a snapshot to an external drive, it will take about the same amount of space as the original share.  This adds up quickly.

 

Message 4 of 13
jak0lantash
Mentor

Re: Backup fails after upgrade to 6.6.1


@StephenB wrote:

Note that the 30 GB used for snapshots is the incremental space needed to store the snapshot.  When you back up a snapshot to an external drive, it will take about the same amount of space as the original share.  This adds up quickly.


I thought this was fixed a long time ago, is it still happening? When backing up a volume or a share to an external, it should NOT transfer the snapshot. As you said, it would duplicate the data (reconstructing the data) and explode in terms of volume. But my understanding was this behavior was changed by not transfering the snapshots when backing up to an external storage.

Message 5 of 13
StephenB
Guru

Re: Backup fails after upgrade to 6.6.1


@jak0lantash wrote:

@StephenB wrote:

Note that the 30 GB used for snapshots is the incremental space needed to store the snapshot.  When you back up a snapshot to an external drive, it will take about the same amount of space as the original share.  This adds up quickly.


I thought this was fixed a long time ago, 


I don't think it was (at least not for full local backups).

 

Of course if doing this resolves the problem, then it's clear it wasn't fixed.

Message 6 of 13
jak0lantash
Mentor

Re: Backup fails after upgrade to 6.6.1

Not saying I trust KBs to be up to date, but this goes in your direction:

https://kb.netgear.com/29654/How-do-I-back-up-data-from-my-ReadyNAS-OS-6-system-to-a-USB-disk

"Note: You may also select the entire data volume as the source of the backup but keep in mind that all snapshots will also be backed up. If the snapshots reference a large amount of data, then the destination device may not be large enough."

 

That said, I remember we used to use rsync backup jobs to USB device and exclude the snapshot folder to work around this "issue", and I was quite sure that this was "fixed". I can't find any release notes mentionning it though. I'll investigate this and let you know.

Message 7 of 13
Freddeco
Aspirant

Re: Backup fails after upgrade to 6.6.1

i turned off snapshot and even tried to backup only one share folder. not the all nas. still it fails.

 

thx

Frederic

Message 8 of 13
Freddeco
Aspirant

Re: Backup fails after upgrade to 6.6.1


@jak0lantash wrote:

Not saying I trust KBs to be up to date, but this goes in your direction:

https://kb.netgear.com/29654/How-do-I-back-up-data-from-my-ReadyNAS-OS-6-system-to-a-USB-disk

"Note: You may also select the entire data volume as the source of the backup but keep in mind that all snapshots will also be backed up. If the snapshots reference a large amount of data, then the destination device may not be large enough."

 

That said, I remember we used to use rsync backup jobs to USB device and exclude the snapshot folder to work around this "issue", and I was quite sure that this was "fixed". I can't find any release notes mentionning it though. I'll investigate this and let you know.



that's what used to work for me before. like the past two years.

 

any way of doing a backup without the snapshots ? 

Message 9 of 13
StephenB
Guru

Re: Backup fails after upgrade to 6.6.1


@Freddeco wrote:

@jak0lantash wrote:

Not saying I trust KBs to be up to date, but this goes in your direction:

https://kb.netgear.com/29654/How-do-I-back-up-data-from-my-ReadyNAS-OS-6-system-to-a-USB-disk

"Note: You may also select the entire data volume as the source of the backup but keep in mind that all snapshots will also be backed up. If the snapshots reference a large amount of data, then the destination device may not be large enough."

 

That said, I remember we used to use rsync backup jobs to USB device and exclude the snapshot folder to work around this "issue", and I was quite sure that this was "fixed". I can't find any release notes mentionning it though. I'll investigate this and let you know.



that's what used to work for me before. like the past two years.

 


It could be that the number of snapshots has hit a threshold, so they no longer fit.

 

Though to be clear, we don't know that it's a snapshot-related issue.  

 

What format is the USB drive?  Can you look at what's saved on it by connecting it to a PC?


@Freddeco wrote:
any way of doing a backup without the snapshots ? 

Start by making the settings change I suggested above (turning off snapshot accessibility on each share).

 

 

Message 10 of 13
Freddeco
Aspirant

Re: Backup fails after upgrade to 6.6.1

hi,

 

snapshot does not appear on the share and i deleted most snapshots keeping only  the last 7 and i still got a disk full.

 

thx

Frederic 

Message 11 of 13
jak0lantash
Mentor

Re: Backup fails after upgrade to 6.6.1

The point is not "how many snapshots" but "is it transferring snapshots". Did you try @StephenB suggestions?
Snapshots are at block level, understand that they contain only the blocks that are different from a reference, which makes them very efficient is used space.
Traditional backups, such as what you're using, occurs at file level. It doesn't have a clue that it's a snapshot, it only considers the files it sees - the full files - the files reconstructed with the blocks in the snapshot merged with the reference(s) - the files like you would see if you were to browse the share.
If the backup tries to transfer a single snapshot, it would require the whole file size, two snapshots, twice. If you have a share with two empty snapshots and transfer the data and the snapshots, it requires THREE times the space.
In FAT, there are other limitations, like the maximum size of a file, which is much lower than the maximum file size on BTRFS. If you were to try transfer a file too big for FAT, it would fail.
Message 12 of 13
Freddeco
Aspirant

Re: Backup fails after upgrade to 6.6.1


@jak0lantash wrote:
The point is not "how many snapshots" but "is it transferring snapshots". Did you try @StephenB suggestions?
Snapshots are at block level, understand that they contain only the blocks that are different from a reference, which makes them very efficient is used space.
Traditional backups, such as what you're using, occurs at file level. It doesn't have a clue that it's a snapshot, it only considers the files it sees - the full files - the files reconstructed with the blocks in the snapshot merged with the reference(s) - the files like you would see if you were to browse the share.
If the backup tries to transfer a single snapshot, it would require the whole file size, two snapshots, twice. If you have a share with two empty snapshots and transfer the data and the snapshots, it requires THREE times the space.
In FAT, there are other limitations, like the maximum size of a file, which is much lower than the maximum file size on BTRFS. If you were to try transfer a file too big for FAT, it would fail.

 

it was indeed the snapshot ot a home user folder that was the culprit. 

 

thanks for the help.

 

regards,

Frederic 

Message 13 of 13
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