Saturday, 3 August 2013

which VM backup should be more reliable ?

Type of VM backup through Symantec
agent-based backup is also known as guest based backup. An agent is installed in every virtual machine and treats each virtual machine as if it was a physical server. The agent in this scenario is reading data from disk and streaming the data to the backup server
  • Both physical and virtual machines are protected using the same method
  • Application owners can manage backups and restores to guest OS
  • Time tested and proven solution
  • Meets their recovery needs
  • This is the only way to protect VMware Fault Tolerant virtual machines and VMs with Physical Raw Disk Mappings RDMS
  • Significantly higher CPU, memory, I/O and network resources utilization on virtual host machines when backups run.
  • Need to install and manage agents on each virtual machine
  • Cost may be high for solutions that license on a per agent basis as opposed to per hypervisor based licensing
  • lack of visibility into changing virtual infrastructure
  • No visibility for backups from VM administrators’ point of view; for example, backups are not visible at vSphere client level
  • Complex disaster recovery strategies
  • Lack of SAN transport backups to offload backup processing job from virtual infrastructure
  • No protection for offline virtual machines and virtual machine templates
  • Slow file by file backup by agent sending the even unchanged data over and over again

Agentless backup-
Agentless backup, also known as host-based backup, refers to solutions that do not require an agent to be installed on each VM by the administrator. However, it’s important to note that the software may be injecting an agent onto the guest machines without your knowledge.
  • VMs can be backed up online or offline
  • Less CPU, memory, I/O and network impact on the virtual host
  • An agentless architecture doesn't require the management of agent software
  • No per VM agent licensing fees
  • Extremely difficult to recover granular object data - first restore the entire VM and its virtual disks
  • Traditional login techniques to log into the server
  • Temporary “injected” drivers can destabilize the system and compromise data integrity
  • Troubleshooting is more complex when using injected (temporary) agents
  • A centralized controller is a single-point-of-failure
  • Requires a fully-virtualized environment. Physical machines still require agent-based backup. If you have physical and virtual you will need two backup solutions – one for physical and the other for virtual.

Agent-Assisted Backup-
Agent assisted backups are also known as host based backup and integrate with VMware’s VADP and Microsoft VSS to provide fast and efficient online and offline backups of ESX, vSphere and Hyper-V. The primary difference between agentless and this design is its perspective: it pairs the VMware VADP or Microsoft VSS with an agent that gathers application metadata to enable multiple avenues of recovery (full VM, applications, databases, files, folders and granular objects).
  • The backup is for the entire virtual machine. This is important because it means the entire VM can be recovered from the image.  It also means that products like Backup Exec & NetBackup can offer “any-level” of recovery from the image contents: Files / Folders, Databases and Granular database contents, like email and documents.
  • The backup can be offloaded from both VM as well as the hypervisor. This means that Backup Exec & NetBackup have the flexibility to offload VM backup onto an existing backup server, instead of burdening the hypervisor.  It also means that users have the option of deploying a dedicated VM, e.g. a virtual appliance, when a physical backup server is not practical.
  • Application owner can self-serve restore requests: The application owner can request restores directly back to the application.
  • Enhanced security: The agent installed for assisting with VM backup can be managed by the application owner. Thus you are avoiding the need to share guess OS credentials with backup administrator.
Best Way to store Backup-
  1. Backup VM directly from storage location for example, SAN, iSCSI, NAS, without having to install any software agent inside the VMs
  1. Centralized backups for Virtual machines
  2. Keep all schedule in simple way for easily understand, thing wrest scenario and make backup plan
  3. Make it documented for every backup policy.

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