VMWare Backup consumed space on DataStore

[Arturo_Lopez]

Hello,

Actually we are having a space problems in some dataStore of VCenter. The problems seems to occur after take a backup of VMWare. I need to know if when netbackup take a backup from VMware in her father job this cosumed space of DataStore.  I thought that when Netbackup make a backup of VMware, firstly take a snapshot that no consume space and after transport this snapshot to the Backup storage but really now i don't know what it's the correct process because the errors on the DataStore seems to be produced about the Snapshot.

Regards.

[sdo · Accepted solution]

As soon as a VMware snapshot becomes active then *ALL* disk IO writes/updates are cached in to a write pending log, i.e. the snapshot. The snapshot can grow rapidly for very active guest virtual machines. It is best practice in VMware to leave 15% to 20%, or more, free space within a VMFS datastore when there are VMs in the datastore which require backups.

[Mark_Solutions]

As well as the snapsot taking up space, if you are running BLIB (block level incremental backups) then CBT (Change Block Tracking) comes into play and will start creating extra files which also take up some of your datastore disk space and grow as time goes on between backups.

[Arturo_Lopez]

Actually we not using BLIB and CBT. There is any document that explain the process of snapshot from Netbackup.

[Mark_Solutions]

As far as i know it is the same as a snapshot created by vCenter .. it is requesetd by the bpfis process on the Netackup VMware backup host and passes the requirements as laid out in your VMware policy to vCenter to actually create the snapshot.

[Mark_Solutions]

In addition to my last ..... Here is a handy place to start if you want to know more https://www.veritas.com/community/blogs/nuts-and-bolts-netbackup-vmware