Vembu BDR Suite » Getting Started with Vembu BDR Suite » Vembu BDR Backup / Offsite DR Server Sizing

Vembu BDR Backup / Offsite DR Server Sizing

Scalability and Infrastructure Sizing

Database Storage

  • Make sure you have 10% free space available in the DB metadata storage target. For example, if you want to backup VMs with 2TB used data, after storage reduction, approximately 1TB data will be stored at storage targets. In this scenario, approximately 100GB free space would be required to store the metadata files.

Storage Repositories

  • You can use any NAS, SAN, or Directly Attached Storage device to store the backup data. There are no limitations with any hardware vendor. So, we never recommend any specific hardware vendor.
  • The performance of the backup job depends on the IOPS. So, you will get better backup performance, if you have higher IOPS.

Information Note:

To calculate the required storage space for your environment, use the Vembu Storage Calculator

VMBackup Client Sizing Table

The following tables illustrate how the VMware & Hyper-V backup performance parameters change depending upon the average data transfer rate.

Underlying Assumptions

  • The estimates provided below are not ‘stretch estimates’; they are safe estimates and are more pessimistic than optimistic. Typical bottlenecks you should look out for are:
    • Bandwidth bottlenecks
    • Slowing down of data transfer due to low-performance switches/routers,  etc.
    • The hard disk write speeds at the storage targets
    • CPU utilization by other non-related processes running on the BDR Backup Server

Sizing Tables

BDR Backup Server Configuration

OS Windows 2012 R2 DC (Physical Machine)
CPUIntel XEON CPU 2.10 GHz (4 cores)
Network1 Gbps
BDR Server Versionv4.0.0

Backup Environment

HypervisorVMware vSphere
No. of VMs16 GB
VM data1 Gbps

Backup Type VM Data Size CPU Utilization Memory Consumed Total time taken to complete the backup Transfer rate 
Full Backup 2 TB 22 % 3145 MB 383 Mins 803 Mbps 
Incremental 55 GB 16.5 % 401 MB 11 Mins 751 Mbps 

Information Note:

The above measurements are taken for one backup job with one VM. So, if multiple concurrent backup jobs are active then it will share the memory and CPU. As stated earlier, each backup job will approximately require 500 MB RAM.  

  • It is important to note that there are no inherent scalability restrictions for a BDR Backup Server when it comes to the maximum number of simultaneous backups possible.
  • If a larger number of backup jobs are simultaneously configured to a BDR Backup Server, then the only effect will be a corresponding degradation of performance in terms of time taken to complete the backup for all the backup jobs.
  • The maximum number of backup jobs that can be supported by a single BDR Backup Server depends on:
    • The bandwidth of the network used
    • Time taken for each backup job
  • For example, the above illustration assumes that backups are typically scheduled during ‘non-office hours’ (hence the 10-hour window); this is not always the case. Especially,  if in case the backups can happen non-intrusively in the background while you do your regular work.

Storage Device Throughput And Concurrent Writes

  • The throughput of Storage devices (IDE/SCSI/SAS/NAS/SAN) is normally benchmarked based on maximum throughput achieved while performing sequential writes into the device.
  • But when multiple VMs are backed up simultaneously to the BDR Backup Server, then the server will be concurrently writing the different files for different VMs onto the Storage device.

Information Note:

When concurrent writes from multiple threads are being done, the throughput of the storage device determines the BDR Backup Server’s performance

  • The reason storage devices do not perform well when multiple threads are writing to it concurrently is that the I/O seek that has to be done between writes from different threads can slow down the performance significantly.
  • Hence, it is imperative that the storage device used to back up the data is of the highest quality and has the ability to scale and perform well when 100s of different threads write to the storage device concurrently.