Item Prefetch Cache configuration options

Article:HOWTO58813  |  Created: 2011-08-01  |  Updated: 2013-07-12  |  Article URL http://www.symantec.com/docs/HOWTO58813
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Item Prefetch Cache configuration options

Use these settings to configure the Discovery Accelerator prefetch cache mechanism. This mechanism retrieves and caches items from the vault store during a scheduled window every night, instead of retrieving each item when the user chooses to review it. The cache therefore helps to speed up the rendering of items in the Review pane. You can specify the size, location, and other characteristics of the cache.

To optimize performance in an environment where you review items very intensively, we recommend the following:

  • Use the fastest storage available and set aside a full partition so that there is no competition for I/O.

  • Set the maximum size within the cache to match the partition size.

  • Set the cache to 365 days before expiry.

  • Set the cache to retrieve the full items with HTML and MSG. If you do not need to export the items, you can choose to retrieve the items with HTML only.

The Item Prefetch Cache options are the more commonly used cache options. You can also set the Item Prefetch Cache (Advanced) options.

Cache enabled

Specifies whether to enable or disable the prefetch cache. By default, Discovery Accelerator disables the cache. Therefore, prefetching does not occur and the cache is not used for item retrieval, even if there are items in the cache. Only enable the cache for a Discovery Accelerator database in which you actively review items or where you connect to slow storage for export runs.

We recommend that you do not enable the prefetch cache in any databases that you use primarily for legal hold searches. This generates a lot of unnecessary network traffic and consumes storage space.

Note that the cache is either enabled or disabled for an entire database.

Cache location

Specifies the local path or network share path to the folder in which to store the cache. Within this folder, Discovery Accelerator stores the prefetched files in a subfolder that is called AcceleratorPrefetch_CustomerId.

Note the following:

  • We recommend that you specify a local path, where possible. If you must specify a network share path, always use the UNC path rather than a mapped drive.

  • The folder must already exist; Discovery Accelerator does not create it.

  • In a hosting environment, multiple customers must not share the same folder.

Cache maximum item age (days)

Specifies the number of days for which items can remain in the cache before Discovery Accelerator automatically deletes them. The item age is based on the creation time of the file in the cache, and not the time that Discovery Accelerator captured the item or the time that the item was originally sent. The default age is 5 days.

Discovery Accelerator may remove an item from the cache earlier than the maximum item age if the cache becomes full.

Cache maximum size (Mbytes)

Specifies the maximum size of the cache in megabytes (MB). The default is 1000 MB. The larger the value of the "Cache maximum item age (days)" setting, the higher the cache maximum size must be to accommodate the items.

End prefetching time of day (server local time)

Specifies the time of day at which Discovery Accelerator stops prefetching items. The default is 05:00 A.M. Use this setting with "Start prefetching time of day" to determine the hours of the day that prefetching is active. Configuring a period during which caching does not occur lets you undertake other maintenance activities during this period, such as performing Enterprise Vault backups.

To make prefetching active at all times, set this option and "Start prefetching time of day" to the same time.

Start prefetching time of day (server local time)

Specifies the time of day at which Discovery Accelerator starts to prefetch items. The default is 20:00 P.M. Use this setting with "End prefetching time of day" to determine the hours of the day that prefetching is active. Configuring a period during which caching does not occur lets you undertake other maintenance activities during this period, such as performing Enterprise Vault backups.

To make prefetching active at all times, set this option and "End prefetching time of day" to the same time.

See Setting Discovery Accelerator system configuration options

See Item Prefetch Cache (Advanced) configuration options


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