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Druva Documentation

About Phoenix backup proxy for VMware

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To register your virtual machines, you have to deploy the Phoenix backup proxy in your infrastructure that registers your server and detects all virtual machines on the server.  The Phoenix backup proxy is described below. 

What is a Phoenix backup proxy?

Backup proxy is a client-side component which is installed on each VMware ESXi Hypervisor or ESXi Host, managed through vCenter Server that manages your virtual machines.

Backup proxy is the component that performs backup and restore of virtual machines. In addition, it is responsible for injecting the guest OS processes into a specific VM to perform application-aware backups. At the moment, the backup proxy supports the backup of Microsoft SQL Server databases. The Phoenix Cloud is the server component that assigns storage on the cloud for backups. The backup proxy performs the backup of virtual machines and SQL Server databases and sends the backed up data to the assigned storage. 

After deploying a backup proxy, you must register it with Phoenix for backing up and restoring virtual machines in your VMware setup.

You can deploy multiple number of backup proxies depending on the number of virtual machines that you want to backup. These multiple number of backup proxies can be logically grouped - named backup proxy pool, and Phoenix then dynamically picks up the best backup proxy that backs up the virtual machines. For more information on how to calculate the required number of backup proxies in your environment, see Sizing for backup proxy.

How does backup proxy work?

This diagram illustrates how backup proxy backs up your VMware setup.

To get started, deploy backup proxy for your VMware setup. If you deploy backup proxy in a vCenter controlled environment and register it with vCenter credentials, the backup proxy will perform the backup of all virtual machines across hypervisors that are associated with the vCenter Server. If you deploy backup proxy on a standalone ESXi host environment and register it with standalone credentials then it will perform the backup of the virtual machines that are created on that ESXi host.

Following the schedule that administrators create, Phoenix Cloud instructs the backup proxy to start backup of virtual machines. Backup proxy performs a backup of virtual machines by creating snapshots of these virtual machines. and sending these snapshots to the assigned storage. 

For image-level backups, the backup proxy uses the vStorage APIs for Data Protection (VADP) to perform backups. It leverages the Change Blocked Tracking (CBT) mechanism to send only the changed blocks since the last backup to Phoenix Cloud. For more information on CBT, see Changed Block Tracking (CBT).

For application-aware backups, the backup proxy injects guest OS processes to back up applications running inside the virtual machine. At the moment, Phoenix supports backup and restore of Microsoft SQL Server databases. The guest OS processes that the backup proxy injects into the virtual machine uses Microsoft's Volume Shadow Service (VSS) APIs to take persistent backups of the Microsoft SQL Server instances. For more information on how Phoenix backs up Microsoft SQL Server databases running inside the VM, see Workflow of application-aware backups on VMware virtual machines.

You can deploy backup proxy to back up,

  • VMs on Standalone VMware ESXi (ESXi) host
    • You require at least one installation of backup proxy for each VMware ESXi hypervisor. Backup proxy is also installed as a virtual machine, and it performs the backup and restore operations of the virtual machines that are installed on that Standalone ESXi hosts.
  • VMs on VMware ESXi hosts managed through VMware vCenter Server (vCenter Server)
    • You require at least one installation of backup proxy for every vCenter Server in your virtual environment. However, you can deploy one or many backup proxyy on any ESXi host managed by a single vCenter Server. 
    • Backup proxy on vCenter Server backs up virtual machines created across hosts that are associated with vCenter Server. 

Note:

  • Backup proxies once deployed with Vcenter credentials will only protect the VM's hosted on ESXi managed by the Vcenter and not from a Standalone ESXi host.You must deploy a separate proxy for the standalone host as well.
  • You can deploy multiple instances of backup proxy for a single ESXi hypervisor or vCenter Server. A single deployment of a backup proxy can be mapped to a single instance of ESXi hypervisor or a vCenter Server, but not both.
  • After you deploy backup proxy for an ESXi hypervisor or vCenter server, you must configure it to reflect the credentials of this hypervisor or vCenter Server.

About backup proxy deployment

You can deploy multiple instances of backup proxy. Factors to consider while planning to deploy multiple instances are,

  • Vastness of your virtual infrastructure – If your organization is geographically distributed and you have deployed virtual machines with multiple backup servers installed across different locations, then you must consider the ease of administration and plan deployment of backup proxy appropriately.
  • Ease of administration –
    • If you choose to deploy backup proxy through VMware vCenter Server, you must install at least one backup proxy in the vCenter-managed infrastructure. Then, one or more instances of backup proxy backup virtual machines are created across hosts associated with vCenter Server.
      Note: If you deploy backup proxy in a vCenter Server controlled environment and register it with vCenter credentials, the backup proxy will perform the backup of all virtual machines across hypervisors that are associated with the vCenter Server.
    • If you choose to deploy backup proxy on VMware ESXi hypervisor or host, then you must install backup proxy on each ESXi hypervisor. Then, one or more instances of backup proxy are created on the associated host.
      Note: If you deploy backup proxy on a standalone ESXi host environment and register it with standalone credentials then it will perform the backup of the virtual machines that are created on that ESX host.

Prerequisites to install backup proxy

Backup proxy is available as an OVA file and is based on CentOS binaries. Deploying a backup proxy creates a new virtual machine of the following configuration:

  • 6 GB RAM
  • 4 virtual disks (40GB, 60GB and 2 disks with 1MB each)
  • 8 vCPU (2 virtual sockets with 4 cores per socket)

You can deploy multiple instances of backup proxy for a single ESXi host or vCenter Server. Ensure that your VMware setup has sufficient resources for a backup proxy deployment. Below is the required configuration that must be available in order to deploy backup proxy.

Resource Minimum requirement
Download size 1.5 GB for extracting the backup proxy
Virtual disk 40 GB thin provisioned disk
CPU 4 virtual CPUs (2 GHz)
RAM 4 GB
  • Ensure you have subscribed to adequate Phoenix storage - Based on the data size that you are planning to backup, you must plan to subscribe enough Phoenix storage. To determine the exact requirement, you can contact Druva Support, who will analyse and help you determine Phoenix storage requirements.
  • Phoenix does not support ESXi hypervisor passwords that contain the character @ (at sign). If the password for an ESXi hypervisor on which backup proxy is deployed contains "@", change the password to remove this sign before you register and configure backup proxy.

Resource sizing for backup proxy

Backup proxy is available as an OVA file and is based on CentOS binaries. The backup proxy OVA file is available on the Downloads page.

Deploying a backup proxy creates a new virtual machine of the following configuration:

Important: Deploying a backup proxy creates a new virtual machine with the below configuration. To ensure that backup proxy behaves as expected, we recommend that you do not install additional applications on this virtual machine.

Parameter Default Configuration
vCPU 8 vCPU (2 virtual sockets with 4 cores per socket)
RAM 6 GB
Virtual disks 4 virtual disks (40GB, 60GB and 2 disks with 1MB each).

With the above default configuration, you can backup upto 3 virtual machines in parallel. 

Note: If you change the backup proxy configuration listed above, additional changes in the backup proxy settings are required to:

  • Ensure concurrent backup jobs
  • Avoid any impact on the CPU

 For more details, contact Druva Support.

This following table illustrates the versions and its supported configuration and concurrent virtual machine backups:

Backup proxy version Configuration Concurrent virtual machine backups
Upto version 4.3-r6381 6 vCPU (3 virtual sockets with 2 cores per socket) and 6GB RAM 5
Version 4.4-r6582 and above 8 vCPU (2 virtual sockets with 4 cores per socket) and 6GB RAM 3

In case you provide a configuration lesser than the default configuration, you cannot POWER ON the backup proxy post deployment. One the following error will be displayed on the screen.
 

To resolve the error, you must manually adjust the number of vCPU's and RAM memory.  Post adjustment, POWER ON the backup proxy.

Minimum configuration

The minimum supported configuration for backups to run without any issues is 3 vCPU and 3 GB RAM. With this configuration, you can backup only 1 virtual machine at a time.

Sizing guidelines for backup proxy

Rules:
•    Each virtual machine backup requires 2 vCPUs and 1.3 GB RAM. 
•    Additionally, 30% of CPU resources and 2 GB RAM are required for operations, such as file level restores, log uploads, and so on.

In case you provide higher configuration to the backup proxy, the right configuration of vCPU and RAM can be achieved by the rules stated above.

The configuration is a function of the number of concurrent backups you want to achieve in your environment.

Calculating concurrency

Say, you have a backup proxy configuration of vCPUs and GB RAM. The number of concurrent backups can be calculated using the following formula:

Number of concurrent backups = Minimum { (X*0.7)/2, (Y-2)/1.3 }  

Example 1: If you have 16 vCPUs and 16 GB RAM in your setup, you can calculate the number of concurrent backup operations that can run as follows:

Number of concurrent backups = Minimum { (16*0.7)/2 = 5.6, (16-2)/1.3 = 10.7 } = 5.6  

You can run up to 6 concurrent backup operations (after rounding the last decimal).

Correspondingly, you can now calculate your ideal RAM configuration to save system resources.

Optimal RAM configuration required to run 6 concurrent backups = (6*1.3)+2 = 9.8

You can optimize your setup to 10 GB RAM (rounded to nearest available unit) since the number of concurrent backups is governed by the vCPU configuration. Vice versa will be applicable in case the number of concurrent backups is derived from the RAM configuration.

Example 2: If you have 16 vCPUs and 8 GB RAM in your setup, you can calculate the number of concurrent backup operations that can run as follows:

Number of concurrent backups = Minimum { (16*0.7)/2 = 5.6, (8-2)/1.3 = 4.6 } = 4.6  

You can run up to 5 concurrent backup operations (after rounding the last decimal).

Correspondingly, you can now calculate your ideal vCPU configuration to save system resources.

Optimal vCPU configuration required to run 5 concurrent backups = (5*2)*1.3 = 13

You can optimize your setup to 13 vCPUs (rounded to nearest available unit) since the number of concurrent backups is governed by the RAM configuration. 

Calculating the required vCPU and RAM

Alternatively, you can calculate the vCPU and RAM configuration by deciding the number of concurrent backups you want to for your environment. 

Example: If you have to backup 50 virtual machines in a 14 hour window and each virtual machine requires approximately 1 hour for backup. 

Thus you need 50/14 = 3.6 = ~4 virtual machines to proceed in parallel backup. 

In case you have to run 4 concurrent virtual machine backups in the environment. You can calculate the number of vCPUs and RAM configuration as follows:

vCPUs required = (4*2)*1.3 = 10.4 

RAM required = (4*1.3) + 2 = 7.2

You need at least 10 vCPUs and 7 GB RAM for 4 concurrent backups.