Different types of VMWare backups in TSM for Virtual Environments and their advantages and disadvantages


You can take different types of virtual machines backups by using TSM BA client and TSM for VE softwares. From BA client command line,  Backup VM command can be used to back up both Microsoft Hyper-V virtual machines and VMware virtual machines. One or more virtual machines can be backed-up using the Tivoli Storage Manager data mover node. Data mover node is the name given to a configuration where the Backup-Archive Client runs on a vStorage backup server and is configured to protect the virtual machines in a Virtual Center or ESX/ESXi server. You can also use the -vmbackuptype and -mode options to indicate how the backups are to be performed. 

Types of VM backups with TSM for VE

-vmbackuptype
Use the -vmbackuptype option with the backup VM command  to specify the type of virtual machine backup to complete. You can also place this option in the client options file (dsm.opt), or on the command line. Different options available for this parameter are

FIle
Specifies a file-level backup to be performed.

FUllvm
Specifies that a full VM backup to be performed. This is the default backup type.

HYPERVFULL
Required for Hyper-V systems. Specifies a full virtual machine backup of all virtual machines that are defined on the Hyper-V host machine. If the vmbackuptype=hypervfull option is specified, most of the other options associated with backing up files from a vStorage backup server are not allowed, they are ignored.

Also Read: Quick Steps to configure TSM for Database (TDPOracle & TDPSQL) and TSM for Mail (TDPExchange & TDPDomino) 

-mode
Use -mode option with the backup VM command to indicate how the VM backups are to be performed. Different types of parameters available are

Full 
Full mode specifies that you want to perform an image backup of all objects on a VMware virtual machine’s disks. 

Incremental
Incremental mode specifies that you want to create an image backup of only the objects that have changed since the last backup. You must have license to use Tivoli Storage Manager for Virtual Environments to use this mode.

IFFull 
IFFull stands for incremental forever full VM backup. In this mode, a snapshot of all used blocks on a VMware virtual machine’s disks are backed up to the server. You must have license to use Tivoli Storage Manager for Virtual Environments to use this mode.

IFIncremental
IFIncremental stands for incremental forever, incremental. In this mode, a snapshot is created of the blocks that have changed since the last backup. You must have license to use Tivoli Storage Manager for Virtual Environments to use this mode.

Taking Virtual machines full backups

Full virtual machine backup processing backs up a virtual machine from a virtual machine-based host. A full VM backup stores a backup copy of all virtual disk images and configuration information for a virtual machine. Full VM backups enable a complete restore of a virtual machine, but they take more time and more server space than a file-level or incremental backup. For example
dsmc backup vm vmname -vmbackuptype=fullvm -mode=full

How it works ?
Full virtual machine backup processing stores a backup copy of all virtual disk images and configuration information for a virtual machine.

Advantages
With full virtual machine backup processing, you get faster data movement than a file-level backup.

Disadvantages
  • Backups are not granular.
  • Full virtual machine backup operations enable a complete restore of a virtual machine, but they take more time and more server space than a file-level or incremental backup.
  • You can restore individual files from a full virtual machine backup only with IBM Tivoli Storage Manager for Virtual Environments.
  • This method is only available on Linux and Windows clients.

Taking VM incremental backup

You can run an incremental backup of a virtual machine from a VMware ESX or ESXi-based host. Incremental backup processing requires a Tivoli Storage Manager for Virtual Environments license. For example
dsmc backup vm vmname -vmbackuptype=fullvm -mode=incremental

How it works ?
An incremental backup of a virtual machine backs up all changes that occurred since the previous backup of the virtual machine, whether the backup was a full backup, or another incremental backup.

Advantages
Incremental backup processing backs up changes to virtual machines between full virtual machine backups.

Also Read: IBM Spectrum Protect (TSM) Administration Certification Questions

Disadvantages
  • The size of incremental backups can increase if you do not run a full backup regularly.
  • It is inefficient to restore data from incremental backups because the process must automatically complete the following tasks:
                   – Restore the most recent full backup.
                   – Restore each incremental backup up to the specified recovery point.
  • This method is available only on Linux and Windows clients.

Taking Virtual machine incremental-forever-full backup

Incremental-forever-full virtual machine backup processing backs up all the used blocks on a virtual machine's disks. To run this type of backup, the system that hosts the Hyper-V server must run Windows Server 2012 R2 or a newer Windows Server operating system. For example
dsmc backup vm vmname -vmbackuptype=fullvm -mode=IFFull

How it works ?
The following processes occur during incremental-forever-full virtual machine backup processing
  • A full virtual machine backup is required only one time.
  • Data from incremental backups is combined with data from the full backup to create a synthetic full backup image. This type of full backup is called a synthetic backup because it is created from the data that is stored on the server and not from reading the used blocks on the production disks.
  • Each incremental-forever-full virtual machine backup operation reads and copies all of the used blocks, whether the blocks are changed or not since the previous backup.
Advantages
  • Periodic full backups are no longer necessary.
  • During a restore operation, you can specify options for a point in time and date to recover data. The data is restored from the original full backup and all of the changed blocks that are associated with the data.
Disadvantages
  • If one or more of the progressive incremental backups is corrupted on the server, you might not be able to fully recover a virtual machine. To ensure that you can fully recover a virtual machine, periodically run a full virtual machine backup.
  • This method is available only on Linux and Windows clients.

Taking Virtual machine incremental-forever-incremental backup

Incremental-forever-incremental backup processing backs up only the disk blocks that have changed since the last backup. For example
dsmc backup vm vmname -vmbackuptype=fullvm -mode=IFincremental

How it works ?
The following processes occur during incremental-forever-incremental backup processing of a virtual machine
  • A full virtual machine backup is required only one time.
  • A full virtual machine backup operation copies all of the used disk blocks that are owned by a virtual machine to the Tivoli Storage Manager server.
  • After the initial full backup, all subsequent backup operations of the virtual machine are incremental-forever-incremental backups.
  • This method copies only the blocks that changed since the previous backup, regardless of the type of the previous backup.
  • The server uses a grouping technology that associates the changed blocks from the most recent backup with data that is already stored on the server from previous backups.
  • A new full backup is then effectively created each time changed blocks are copied to the server by an incremental-forever-incremental backup.
Advantages
  • Periodic full virtual machine backups are no longer necessary.
  • This method reduces the amount of data that goes across the network.
  • This method reduces data growth because all incremental backups contain only the blocks that changed since the previous backup.
  • No comparison with the backup target is required since only changed blocks are identified.
  • Impact to the client system is minimized.
  • The length of the backup window is reduced.
  • Data restore operations are simplified.
  • This method optimizes data restore operations.
  • If one or more of the progressive incremental backups is corrupted on the server, you might not be able to fully recover a virtual machine. To ensure that you can fully recover a virtual machine, periodically run a full virtual machine backup.
  • It is available only on Linux and Windows clients.

Taking VMware file-level backup on Windows

On Windows systems, you can use the backup-archive client to create file-level backups of VMware virtual machines. For example
dsmc backup vm vmname -vmbackuptype=file

How it works ?
The following processes occur during file-level backup processing of a virtual machine
  • A VMware snapshot is taken of the virtual machine to be backed up.
  • The file systems of the virtual machine are remotely mapped to the vStorage backup server.
  • A file-level progressive incremental backup is run for all of the file systems.
  • The data is stored under the node name that matches the host name of the virtual machine.
  • The data for each virtual machine is stored in the node that is associated with the virtual machine.
  • The file system mappings are removed and the snapshot is removed.
When to use ?
Use file-level virtual machine backup processing if you want to restore individual files from a virtual machine but you do not have a license for Tivoli Storage Manager for Virtual Environments.

Also Read: Use these Exclude options during backup to save storage pool space

Advantages
  • You can use include and exclude rules to identify the files to back up.
  • Files are backed up as individual files rather than as an image backup.
Disadvantages
  • File-level restores must be made from a backup-archive client that is installed directly on a virtual machine guest.

Taking Parallel backups of virtual machines

You can improve performance of virtual machine backups by running parallel backups of multiple virtual machines by using a single instance of the backup-archive client. For example
dsmc backup vm vmname1,vmname2 -vmbackuptype=file

How it works ?
The following processes occur during parallel backup processing of virtual machines
  • A single Tivoli Storage Manager data mover node can be used to concurrently back up multiple virtual machines.
  • When the backups are initiated, the client establishes parallel sessions to copy the data to the Tivoli Storage Manager server.
Advantages
  • You can optimize the backups so that they do not adversely affect the servers that are hosting the virtual machines.
Disadvantages
You must optimize the parallel backups. The number of virtual machines that you can back up in parallel depends on the following factors
  • The processing power of the server that the Tivoli Storage Manager data mover node runs on.
  • The performance of I/O between the client and the Tivoli Storage Manager server.




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