Application consistency for physical backups
• Crash consistent: A crash-consistent backup is analogous to pulling the plug on a server and then backing up the data. The state of the data that is being backed up with respect to the users of the data is indeterminate. Restoring a crash-consistent image is equivalent to rebooting a server after a hard shutdown.
• Application consistent: vRanger engages the Microsoft VSS to put supported applications into a consistent state during a backup. This option ensures that all application writes requests in the machines memory are committed to disk before the snapshot is taken, which means that the application and data can be reliably recovered from the backup archive.
Understanding retention policies and space-saving technologies
• Full backups: Each savepoint is a complete backup set. Deleting a savepoint has no bearing on the recoverability of any other full savepoint.
• Incremental backups: Incremental backup jobs backup only the blocks that have changed since the last backup — full or incremental. Restoring an incremental savepoint requires the parent full and every incremental between the full and the selected incremental.
• Differential backups: A differential backup contains the data that has changed since the last full backup. Each differential backup includes the contents of the previous differential, which in retention terms means that only the parent full and the most recent differential are required for a restore.Full backups
The following scenario depicts a daily full backup job, with a Savepoint Count of 7:
• Day 1: A full backup is taken.
• Day 2: A full backup is taken.
• Day 3: A full backup is taken.
• Day 4: A full backup is taken.
• Day 5: A full backup is taken.
• Day 6: A full backup is taken.
• Day 7: A full backup is taken.
• Day 8: A full backup is taken. The savepoint from Day 1 is removed.
• Day 9: A full backup is taken. The savepoint from Day 2 is removed.Incremental backups
Incremental backup jobs back up only the blocks that have changed since the last backup — whether it was full or incremental. Restoring an incremental savepoint requires the parent full and every incremental between the full and the selected incremental.
Table 2. Incremental backup retention example
An incremental backup is taken. All savepoints from Day 1 to Day 7 are removed.
Differential backups
Performing optional configurations
Before you set up a backup job, you may want to make the following optional vRanger configurations:
Enabling VMware Changed Block Tracking (CBT)
VMware® CBT reduces the time needed for incremental and differential backups by only backing up the portions of a disk that have changed since the last backup. By determining which blocks changed within the VMDK file, vRanger only backs up the portions of a disk that have changed since the last backup. This often results in shorter backup operations, and reduced resource consumption on network and storage elements.
VMware vSphere® supports CBT, and most VMs running in this environment can use it. The VMs must be Hardware Version 7 or later, and have been created and hosted in VMware® ESXi™ 6.0 or later hosts. VMs that are created in VMware® ESX® 4 or earlier must be migrated to Hardware Version 7 or later for CBT to be supported. CBT must be enabled for each VM with which CBT is to be used.
Change Block Tracking is enabled or disabled on a per-VM basis. There are two methods to enable CBT:
•
• In the My Inventory view, right-click the VM for which want to change the CBT setting, and then select Enable Change Tracking. The Changed Block Tracking Icon appears next to any VM on which CBT is enabled.
© ALL RIGHTS RESERVED. Términos de uso Privacidad Cookie Preference Center