05-07-2012 08:39 PM - edited 08-29-2017 05:22 AM
Data replication applications are dependent on the IP network infrastructure for their performance. Wide Area Networks (WAN) introduce latency, packet loss, congestion and bandwidth limitations that impact data replication performance. Additionally, WAN links are inefficiently utilized, having to transmit repeated data patterns due to the similarity of data in an organization. Data replication traffic has unique characteristics that require dedicated and specialized resources to expedite processing and overcome the challenges and limitations imposed by the WAN. Data replication traffic is by nature high in volume with a low number of TCP connections. These connections are long lived per session and they are persistent over a long time. This is unlike branch office to data center traffic which is low volume with a high number of TCP connections that are short lived per session.
Replication Accelerator provides the following benefits:
● Complete data center storage replication jobs into existing or shorter replication windows.
● Maximize investment in WAN bandwidth for data center storage replication.
● Meet more stringent recovery point objectives (RPO) at a lower cost.
● Extend the distance between disaster recovery sites.
Replication Accelerator Mode was introduced in Cisco WAAS 4.0.19 and is available until 4.0.27. It is not included in 4.1 and above versions. For above versions use feature Application Acceleration..
The WAAS software comes with over 150 predefined optimization policies that determine the type of application traffic your WAAS system optimizes and accelerates. These predefined policies cover the most common type of application traffic on your network. All application definitions configured in the WAAS Central Manager are globally applied to all WAAS devices that register with the WAAS Central Manager, regardless of the device group membership configuration. The global optimization features determine if TFO Optimization, Data Redundancy Elimination (DRE), and Persistent Compression are enabled on a device or device group. By default, all of these features are enabled. If you choose to disable one of these features, the device will be unable to apply the full WAAS optimization techniques to the traffic that it intercepts.
As in a Branch Office-to-Data Center (Application Acceleration) scenario, traffic can be intercepted and/or redirected to a WAE that is enabled for Replication Acceleration. This can be done using one of the following methods:
• Inline (Preferred for Replication Acceleration)
• WCCP (N+1 cluster for High Availability and Load Balancing)
• ACE, CSM module, CSS, or similar device
To obtain an optimal performance for data replication, it is recommended to use `Inline' mode and installing the WAE that will be performing data replication optimization as close as possible to the storage systems. Thus the WAE that is configured for `Replication Accelerator' will not have to receive non-Data Replication (DR) traffic. The `Inline' mode also supports `Port-Channel', which enables load-balancing and `high-availability' should one of the physical link fails. The following configuration example shows how to enable `Replication Accelerator' mode on WAE.
!
device mode replication-accelerator <<<< Enables Replication Acceleration on WAE
!
interface InlineGroup 1/0
ip address 192.168.10.1 255.255.255.0
inline vlan all
exit
It seems that this can only be done by version 4.0.19. Does this mean that I have to downgrade all of my WAEs to use this feature?
No Amir,
Post WAAS 4.0 where there is no Replication Accelerator Mode it is generally recommended to use Application Accelerator Mode with the Policy configured for the Replication Traffic as TFO+LZ. No DRE.
Regards
Kiran.
Thank Kiran for the info but could you please advise as to how I can configure this policy for Replication Traffic?? Any links??
Hi Amir,
This is like any Application Policy configuration, where you can create an Application policy based on the IP address or Port Number and configure the Acceleration Policy to be TFO+LZ.
Please see below the config guide on how to create an Application Policy:
Hope this helps.
Regards
Kiran.
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