Troubleshooting guide

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Cisco Wide Area Application Services Configuration Guide
OL-26579-01
Chapter 1 Configuring File Services
Configuring File Services
About Preposition Directives
A preposition directive allows you to determine which files should be proactively copied from CIFS file
servers to the cache of selected Edge WAEs. Prepositioning enables you to take advantage of idle time
on the WAN to transfer frequently accessed files to selected WAEs, where users can benefit from
cache-level performance even during first-time access of these files.
Prepositioning is supported on automatically discovered file servers in the transparent CIFS accelerator
When defining a preposition directive, you select the Edge WAEs that you want to be prepositioned with
content from the file server, then specify the root directories on the file server to be prepositioned.
Initially, the preposition directive is in the unscheduled state. You must create a schedule that determines
when and how often the content is prepositioned. Because content can be prepositioned on a regular
basis, you can specify whether each new iteration of the task should copy all designated files, or only
those files that have changed over a specified time interval.
In addition, you can specify time and size limits to prevent a preposition task from consuming too much
bandwidth on the WAN or too much space on the Edge WAE cache. We strongly recommend that you
use these limits to optimize network efficiency and prevent misuse of this feature.
When the activation time of a preposition directive arrives, a preposition task starts on the Edge WAE.
Each preposition task can be monitored in the WAAS Central Manager GUI during and after processing.
You can also terminate active preposition tasks if required.
Prepositioning requires that the username and password needed to access the file server be specified.
These items are specified directly in the Creating New Preposition Directive window, as described in the
following procedure.
Note When preposition updates are sent to the Central Manager, if any preposition file server credentials
cannot be decrypted, all further preposition updates are not sent from the WAE to the Central Manager
and decryption failure error messages are logged in errorlog/cms_log.current. You must reconfigure the
preposition credentials from the CLI.
Prepositioning includes the ability to configure multiple roots. See the “Creating a New Preposition
Directive” section on page 1-12.
When using prepositioning, both branch and data center WAEs are required (the same as for any other
accelerated traffic). The branch WAE retrieves prepositioned files through an optimized connection.
Verify that you have connectivity between the following network entities:
• Client to branch WAE
• Branch WAE to data center WAE
• Branch WAE to file server
• Data center WAE to file server
You will need to change any ACLs that might be blocking prepositioning traffic.
Note Though preposition directives can be created and managed by using the CLI, we recommend that you
use the Central Manager GUI because you can manage prepositioning for groups of WAEs from the
Central Manager. If you mix GUI and CLI configuration, unpredictable results can occur because
changes on one device can affect other devices.
The following topics describe how to create and manage a preposition directive:
• Creating a New Preposition Directive, page 1-12