Troubleshooting guide

REVIEW DRAFT—CISCO CONFIDENTIAL
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Cisco Wide Area Application Services Configuration Guide
OL-26579-01
Chapter 1 Introduction to Cisco WAAS
Overview of the WAAS Interfaces
Inline Interception Support
Direct inline traffic interception is supported on WAEs with a Cisco WAE Inline Network Adapter or
Interface Module installed. Inline interception of traffic simplifies deployment and avoids the
complexity of configuring WCCP or PBR on the routers.
An inline WAE transparently intercepts traffic flowing through it or bridges traffic that does not need to
be optimized. It also uses a mechanical fail-safe design that automatically bridges traffic if a power,
hardware, or unrecoverable software failure occurs.
Note AppNav Controller Interface Modules do not support automatic bypass mode to continue traffic flow in
the event of a failure. For high availability, two or more AppNav Controller Interface Modules should
be deployed in an AppNav cluster. For more information on using inline mode with the AppNav solution,
see Chapter 1, “Configuring AppNav.”
You can configure the inline WAE to accept traffic only from certain VLANs; for all other VLANs,
traffic is bridged and not processed.
You can serially cluster inline WAE devices to provide higher availability in the event of a device failure.
If the current optimizing device fails, the second inline WAE device in the cluster provides the
optimization services. Deploying WAE devices in a serial inline cluster for the purposes of scaling or
load balancing is not supported.
For more information about inline mode, see the “Using Inline Mode Interception” section on page 1-42.
Failure Resiliency and Protection
Cisco WAAS provides a high-availability failover (and load-balancing) function that minimizes the
probability and duration of CIFS downtime.
If a WAE configured for CIFS fails, all peer WAEs configured to operate with it are redirected to work
with an alternate WAE. This operation maintains high availability without service interruption.
This change may not be transparent to users, which means that client connections are closed and require
CIFS clients to reestablish their connection. Whether such changes impact currently running
applications depends on the behavior of the application being used, and on the behavior of the specific
CIFS client. Typically, however, the transition is transparent to the client.
RAID Compatibility
Cisco WAAS provides the following Redundant Array of Independent Disks (RAID) capability for
increased storage capacity or increased reliability:
• Logical Disk Handling with RAID-5–Logical disk handling with Redundant Array of Independent
Disks-5 (RAID-5) is implemented in WAAS as a hardware feature. RAID-5 devices can create a
single logical disk drive that may contain up to six physical hard disk drives, providing increased
logical disk capacity.
Systems with RAID-5 can continue operating if one of the physical drives fails or goes offline.
• Logical Disk Handling with RAID-1—Logical disk handling with RAID-1 is implemented in
WAAS as a software feature. RAID-1 uses disk mirroring to write data redundantly to two or more
drives, providing increased reliability.