If the vdisk is 100G , but only 40G is used , will Veaam backup 100G or 40G in first full backup ?
Answer
First VMware Backup from Snapshot
Best answer by MicoolPaul
In the default config, the 100GB is what gets processed, but only the 40GB of needed data is backed up, it’s slightly more complicated than that but give this page a read to understand what can impact this:
https://helpcenter.veeam.com/docs/backup/vsphere/backup_job_advanced_storage_vm.html?ver=110
In essence though, unless you change the settings, Veeam will read the “entire” disk on the first backup, it will ignore deleted blocks, it will also ignore swap files & hibernation files. Of the remaining blocks it will deduplicate & compress so if you’re using only 40GB of your 100GB VM disk size, it wouldn’t be uncommon to still see a 2:1 reduction on your 40GB source data for a 20GB backup, but that all depends on the content!
The above is all true for the initial backup, then for your subsequent incrementals, unless settings are changed, Veeam will used Changed Block Tracking (CBT) to fetch only the changed blocks, then perform the above processing again to ensure only the necessary data is backed up for subsequent restores, these files will rely on the rest of the backup files in the “backup chain”.
The only thing I haven’t gone into detail on here is block sizes, but that’s a further optimisation story that doesn’t relate directly to your question. Read the storage optimisation section here for more detail on that if interested: https://helpcenter.veeam.com/docs/backup/vsphere/compression_deduplication.html?ver=110#optimization
+16It depends on the OS. I have seen that Veeam can determine how much space is used with Windows disks and will read the used space only. With Linix the whole diskspace is read. But in both cases the used space only is transmitted after compression.
So, the backup will be less than 40GB, because of compression (and deduplication, if there are more than one VM in the job).
Jochen (Joe) Meixner | Veeam Vanguard 2024 | Veeam Legend 2021 - 2024 | Veeam Certified Architect (VMCA) | X: @JoMeix | BlueSky: @jmeixner.bsky.social
+23In the default config, the 100GB is what gets processed, but only the 40GB of needed data is backed up, it’s slightly more complicated than that but give this page a read to understand what can impact this:
https://helpcenter.veeam.com/docs/backup/vsphere/backup_job_advanced_storage_vm.html?ver=110
In essence though, unless you change the settings, Veeam will read the “entire” disk on the first backup, it will ignore deleted blocks, it will also ignore swap files & hibernation files. Of the remaining blocks it will deduplicate & compress so if you’re using only 40GB of your 100GB VM disk size, it wouldn’t be uncommon to still see a 2:1 reduction on your 40GB source data for a 20GB backup, but that all depends on the content!
The above is all true for the initial backup, then for your subsequent incrementals, unless settings are changed, Veeam will used Changed Block Tracking (CBT) to fetch only the changed blocks, then perform the above processing again to ensure only the necessary data is backed up for subsequent restores, these files will rely on the rest of the backup files in the “backup chain”.
The only thing I haven’t gone into detail on here is block sizes, but that’s a further optimisation story that doesn’t relate directly to your question. Read the storage optimisation section here for more detail on that if interested: https://helpcenter.veeam.com/docs/backup/vsphere/compression_deduplication.html?ver=110#optimization
Michael Paul - Opinions are my own and do not necessarily reflect the opinion of Veeam | https://micoolpaul.com | Mastodon: @micoolpaul@masto.nu | Bluesky: @micoolpaul.com
+23I see
Michael Paul - Opinions are my own and do not necessarily reflect the opinion of Veeam | https://micoolpaul.com | Mastodon: @micoolpaul@masto.nu | Bluesky: @micoolpaul.com
+12I have seen that Veeam can determine how much space is used with Windows disks and will read the used space only.
I believe, you are referring to a VBR feature called Bitlooker. It is available for VM Backups and works only for NTFS partitions. :)
With this feature, deleted blocks will be ignored and only used space will be analyzed.
Deleted File Blocks (BitLooker) - User Guide for VMware vSphere (veeam.com)
Senior Analyst, Product Management @ Veeam Software
+16I have seen that Veeam can determine how much space is used with Windows disks and will read the used space only.
I believe, you are referring to a VBR feature called Bitlooker. It is available for VM Backups and works only for NTFS partitions. :)
With this feature, deleted blocks will be ignored and only used space will be analyzed.
Deleted File Blocks (BitLooker) - User Guide for VMware vSphere (veeam.com)
Maybe 😎
I just observed this behaviour and could not name it. So, thank you for teaching me what feature this is. 👍🏼
Jochen (Joe) Meixner | Veeam Vanguard 2024 | Veeam Legend 2021 - 2024 | Veeam Certified Architect (VMCA) | X: @JoMeix | BlueSky: @jmeixner.bsky.social
+10Good comments here - thank you
Twitter @RickVanover | Email: rick.vanover@veeam.com
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