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ISExpress
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Backup size increase

Post by ISExpress »

Hi

I have logged with Veeam support but thought I would post on the forum.

Very odd issue.

We currently have 4 backup jobs and over the last few days the size of the backup jobs have grown to a much higher rate. Normally all our jobs are under 1.4tb but now have grown an extra 400gb. It seems now when comparing a recent backup to an older backup. Its also backing up the free space.

I have been tweaking our Veeam setup to try to get better compression as well as improving the time taken for backups so made a change in backup repositories part which was I have ticked the ‘decompress backup data blocks before storing’ in the hope that our backup times would decrease as it seemed we would receive better compression ratios. We have since disabled this option due to the backup size increase.

Veeam is installed on a local Windows server and this has a fibre connection to some Mass Storage by NexSAN. So when Veeam backups it connects directly to the VMware Datastores rather than backup via LAN.

Thanks

foggy
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Re: Backup size increase

Post by foggy »

Is there a chance that your VMs have produced a lot of changes recently (disks were defragmented, for example, or updates installed)?

Or are you saying that backup file size has increased after enabling the 'decompress backup data blocks before storing' setting?

ISExpress
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Re: Backup size increase

Post by ISExpress »

Hi

There hasnt been any major changes to the VMs so am assuming it could be to changing that option.

foggy
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Re: Backup size increase

Post by foggy »

This setting is intended for deduplication targets. When you enable compression for a backup job, backup data is compressed at the source side before being transmitted to the target and this can result in poor deduplication ratios storage appliances can provide (as the number of matching blocks decreases). If this check box is selected, data is decompressed on the target side and raw data is written to the storage device to achieve a higher deduplication ratio. I would assume that Veeam compression provides better results than your target storage deduplication can provide, so after enabling this option the backup size is obviously increased.

Also, regarding you backup time concern, enabling this option significantly affects the duration of the whole backup procedure (data decompression takes time).

ISExpress
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Re: Backup size increase

Post by ISExpress »

That answers that question. I think what I might do is take out the backups out of the folder and then Veeam will create a brand new full veeam backup and hopefully we will see tonight if the size decreases.
Thanks for your advice.

foggy
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Re: Backup size increase

Post by foggy »

If you simply take backups out, the job will fail due to missing VBK file. You should execute the "Perform Full Backup" command manually or wait until the next scheduled full. Actually, no need to bother, the very next increment after disabling decompression will be stored compressed.

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Re: Backup size increase

Post by ISExpress »

Just to let you know we saw the problem on Monday, so on Tuesday I disabled the compression option hoping that last nights backup would return to normal but doesnt look like it did.

We run a full back every Sunday but if I remove the files surely Veeam will detect that it has nothing to append to and then just create a brand new full backup or am i missing something here??

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Re: Backup size increase

Post by foggy »

ISExpress wrote:Just to let you know we saw the problem on Monday, so on Tuesday I disabled the compression option hoping that last nights backup would return to normal but doesnt look like it did.
Seems to work in my lab. Just checked.
ISExpress wrote:We run a full back every Sunday but if I remove the files surely Veeam will detect that it has nothing to append to and then just create a brand new full backup or am i missing something here??
If you remove the vbk, the job will fail (unless you have the ForceCreateMissingVBK key set to 1).

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Re: Backup size increase

Post by ISExpress »

foggy wrote: Seems to work in my lab. Just checked.
If you remove the vbk, the job will fail (unless you have the ForceCreateMissingVBK key set to 1).
You were right! I was wrong. I removed the file and did the jobs did indeed fail. So i manually ran a full backup and the size has drastically decreased.

Thanks

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