Forum ©XSIBackup: ©VMWare ©ESXi Backup Software

rbadal

Member

Registered: 2019-02-18

Posts: 3

Backup size

Hello,

I am using xsibackup to backup my VM's. This is the command i use to backup:

"/vmfs/volumes/datastore/xsi-dir/xsibackup --backup-point=/vmfs/volumes/datastore/VM-BACKUP --backup-type=all --backup-prog=vmkfstools"

I am using THIN provision on my VM's. So lets say if i added a 100GB HDD and it is using only 20GB, in VMware i see used space: 20GB. But when i do the backup, the whole 100GB HDD disk gets backupped. When i check the disk properties, i see that it is using 100GB om my backup destination.

Is there any way i can only backup the size that i actually used in stead of the whole 100GB?

Thanks in advance.

rbadal

Member

Registered: 2019-02-18

Posts: 3

Re: Backup size

Maybe it has something to do with my datastore? I am using VMFS6 as my datastore. I tried to use an NFS datastore, but the same thing happens. When i create a blank VM, the used space is 0MB, but when i access the storage (not via VMware Datastore Browser, but i just mount the NFS storage) i see the size on my disk is the actual size of the HDD i attached to the new VM (so for example the disk is 16GB, even though it is using 1MB). When i backup the VM, i backup the whole 16GB.

See picture for example:

Anyone experiencing the same issue? (Or maybe its not an issue but just the way VMware works with storage?)

Last edited by rbadal (2019-02-19 07:26:42)

admin

Administrator

Registered: 2017-04-21

Posts: 2,055

Re: Backup size

vmkfstools does indeed create thin VMs. The problem is that for this to be possible the underlying file system must support sparse files. VMFS5 does, as well as VMFS6. Regarding NFS, the same happens, you won't be able to retain the sparsness of your files if you backup to an NFS share which underlying file system does not support the feature.

In regards to your Windows file properties screenshot, its showing a sparse file. You are probably being puzzled by what a sparse file is and what to expect seeing when you use certain visual tools.

In a sparse file, the nominal size of the file as seen by the file system is its full size. The only difference is that it's empty space is filled with nulls and some file systems are able to use this to just allocate space for the non-null blocks and thus use space more efficiently.

You probably noticed that vmkfstools didn't copy all data. You can visually notice it, as it jumps over zeroed or nulled zones and the percentage progress jumps along with it, taking a lot less time than expected.

What are sparse files?

rbadal

Member

Registered: 2019-02-18

Posts: 3

Re: Backup size

Thank you for your reply! Indeed, the underlying OS needs to understand the thin provisioning from VMware. VMFS does this, but NFS/CIFS not. I am trying to SCP/RSYNC my backup to the cloud, but then i have to upload the whole size of the disk. I tried the backup with "--backup-prog=xsitools" and then i get the provisioned size and not the whole disksize as backup. The only 'but' is that i need the PRO version to restore my backup.

Is there any other way i can use XSIbackup to backup my provisioned size from my datastore without using an VMFS disk as destination or using XSItools? I want to store an copy in the cloud, and i can only mount my cloud drive through WebDAV/NFS/CIFS.