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Sun Java System Web Proxy Server User Interface 

The Caching Tab


The Caching tab contains the following pages:


The Set Cache Specifics Page

The Set Cache Specifics page is used to enable caching and control the types of protocols your Proxy Server will cache by setting the cache specifics.

The following elements are displayed:

Cache Status. Caching is an effective way to reduce network traffic for users of the Proxy Server. Caching also offers a faster response time for clients by eliminating the need to retrieve a document from a remote server. The cache is enabled by default.

Working Directory. Displays the working directory. By default, the working directory is present under the proxy instance and can be changed if you want the cache directory to be in a different location. All cached files appear in an organized directory structure under the caching directory.

You can extend the cache directory structure to multiple file systems so that you can have a large cache structure divided on multiple smaller disks instead of keeping it all on one large disk. Each proxy server must have its own cache directory structure, that is, cache directories can not be concurrently shared by multiple proxy servers.

Cache Size. Select the cache size from the drop-down list. By default, this is set to 1.6 GB and ranges from 10 MB to 32 GB.

The cache size indicates the partition size. Cache size should always be lesser than the cache capacity as it is the maximum size to which the cache can grow. The sum of all the partition sizes must be less than or equal to the cache size.

The amount of disk space available for the proxy cache has a considerable effect on cache performance. If the cache is too small, the CacheGC must remove cached documents to make room on the disk more often, and documents must be retrieved from content servers more often, therefore slowing performance.

Large cache sizes are best because the more cached documents, the less the network traffic load and the faster the response time the proxy provides. Also, the CacheGC removes cached documents if users no longer need them. Barring any file system limitations, cache size can never be too large; the excess space simply remains unused.

You can also have the cache split on multiple disk partitions. For more information on partitions, see "Adding and Modifying Cache Partitions" in the Proxy Server Administration Guide.


Caution

Changing the cache structure is time-consuming.


Cache Capacity. Click the Cache capacity configuration link. The Set Cache Capacity page appears that is used to set the cache capacity. Cache capacity is directly related to the cache hierarchy in the cache directories. The bigger the capacity, the larger the hierarchy. The cache capacity should be equal to or greater than the cache size. By default, the cache capacity is set to 2 GB and ranges from 125 MB to 32 GB.

Cache HTTP. If you decide that you want your Proxy Server to cache HTTP documents, you need to determine whether it should always do an up-to-date check for the documents in the cache or if it should check based on an interval. You can also enable or disable the Proxy Server from reporting cache hits to the remote server. The options include the following:

Cache FTP. You can set the refresh interval for cached FTP documents. The option includes the following:

Cache Gopher. You can set the refresh interval for cached Gopher documents. The option includes the following:

OK. Saves your entries.

Reset. Erases your changes and resets the elements in the page to the values that they contained before your changes.


The Add/Edit Cache Partitions Page

The Add/Edit Cache Partitions page is used to add and modify cache partitions.

Cache partitions are reserved parts of disks or memory that are set aside for caching purposes. If your caching capacity changes, you may want to change or add partitions using the Cache Partition Configuration page. From this page, you can edit a partition’s location, mnemonic name, and maximum and minimum sizes. You can also view the cache section table for that partition.

The following elements are displayed:

Partition Details. Lists the details of the partitions that have been created. You can edit a partition’s details by clicking the partition name.

Add Cache Partition. Click this button to add a new cache partition. The Cache Partition Configuration page displays the following elements:

OK. Saves your entries.

Reset. Erases your changes and resets the elements in the page to the values that they contained before your changes.


The Manage Sections Page

The Manage Sections page is used to move sections among existing partitions.

The proxy cache is separated into one or more cache sections. You can have up to 256 sections. The number of cache sections must be a power of two (for example, 1, 2, 4, 8, 16, ..., 256).

The smallest available capacity is 125MB with a single cache section. The largest capacity is 32GB (optimum) with 256 cache sections. If you pick a cache capacity of 500MB, the installer will create 4 cache sections (500/ 125 = 4); if you choose a cache capacity of 2GB, the installer creates 16 sections (2000 / 125 = 16).

The following elements are displayed:

Section Details. Lists the details of all the sections. A section can be moved to another partition by selecting the partition from the drop-down list.

OK. Saves your changes.

Reset. Erases your changes and resets the elements in the page to the values that they contained before your changes.


The Set Cache Capacity Page

The Set Cache Capacity page is used to set the cache capacity of the Proxy Server.

The cache capacity should be equal to or greater than the cache size. Setting the capacity larger than the cache size can be helpful if you know that you plan to increase the cache size later, such as by adding an external disk.

The following elements are displayed:

Current Cache Sections. Displays the current cache sections.

Dim. Displays the cache dimensions.

Format. Displays the format of the cache sections.

Current Capacity Range. Displays the current capacity range.

Optimum. Displays the optimum cache capacity.

New Capacity Range. Select a capacity from the drop-down list. The default value is 2 GB.

OK. Saves your changes.

Reset. Erases your changes and resets the elements in the page to the values that they contained before your changes.


The Set Garbage Collection Preferences Page

The Set Garbage Collection Preferences page is used to set the garbage collection mode.

The following elements are displayed:

Cache Garbage Collection Mode. You can use the cache garbage collector to deletes files from the cache. Garbage collection can be done in either the automatic mode or the explicit mode. The explicit mode is externally scheduled by the administrator using the Schedule Garbage Collection page. Select one of the modes and click OK.

OK. Sets the garbage collection mode.

Reset. Erases your changes and resets the elements in the page to the values that they contained before your changes.


The Tune Cache Page

The Tune Cache page is used to view and modify the tuning parameters of the Proxy Server.

The following elements are displayed:

Multiple Byteranges. Determines whether or not the proxy is allowed to generate byte-range responses from the cache. By default, this feature is disabled.

OK. Saves your entries.

Reset. Erases your changes and resets the elements in the page to the values that they contained before your changes.


The Schedule Garbage Collection Page

The Schedule Garbage Collection page allows you to specify the days and time when garbage collection will take place.

The following elements are displayed:

Schedule Garbage Collection At. Specify the time at which garbage collection will occur.

Garbage Collection Days. Specify the day of the week on which garbage collection will occur.

OK. Saves your entries.

Reset. Erases your changes and resets the elements in the page to the values that they contained before your changes.


The Tune Garbage Collection Page

The Tune Garbage Collection page is used to view and modify the garbage collection settings.

Garbage Collection is a resource-intensive process. Therefore, you may need to tune some garbage collection settings to improve its performance.

The following elements are displayed:

GC Hi Margin Percent. Controls the percentage of the maximum cache size that, when reached, triggers garbage collection.

GC Lo Margin Percent. Controls the percentage of the maximum cache size that the garbage collector targets.

GC Extra Margin Percent. Sets the percentage of the cache to be removed by the garbage collector.

GC Leave Fs Full Percent. Determines the percentage of the cache partition size below which garbage collection will not go.

OK. Saves your entries.

Reset. Erases your changes and resets the elements in the page to the values that they contained before your changes.


The Set Caching Configuration Page

The Set Caching Configuration page is used to configure the kind of caching you want for specific resources. You can specify several configuration parameter values for URLs matching the regular expression pattern that you specify. This feature gives you fine control of the proxy cache, based on the type of document cached. Configuring the cache might include identifying the following items:

The following elements are displayed:

Select. Click this button after selecting a resource from the drop-down list.

Regular Expression. Specify a regular expression. For more information, see "Understanding Regular Expressions" in the Proxy Server Administration Guide

Caching Default. The Proxy Server allows you to identify a cache default for specific resources. By default, the Cache option is selected. Your server automatically caches all cacheable documents from that domain.


Note

If you set the cache default for a particular resource to either Derived Configuration or Don’t Cache, you do not need to configure the cache for that resource. However, if you choose a cache default of Cache for a Resource, you can specify several other configuration items. You can set the cache default for any resource on the Set Caching Configuration page. The cache default for HTTP, FTP, and Gopher can also be set on the Set Cache Specifics page.


Caching Pages That Require Authentication. You can have your server cache files that require user authentication. If you choose to have your Proxy Server cache these files, the Proxy Server tags the files in the cache so that if a user asks for them, it knows that the files require authentication from the remote server.

Because the Proxy Server does not know how remote servers authenticate and it does not know users’ IDs or passwords, it will simply force an up-to-date check with the remote server each time a request is made for a document that requires authentication. The user therefore must enter an ID and password to gain access to the file. If the user has already accessed that server earlier in the Netscape Navigator session, Navigator automatically sends the authentication information without prompting the user for it.

Caching Queries. Cached queries only work with HTTP documents. You can limit the length of queries that are cached, or you can completely inhibit caching of queries. The longer the query, the less likely it is to be repeated, and the less useful it is to cache.

These caching restrictions apply for queries: the access method has to be GET, the document must not be protected (unless caching of authenticated pages is enabled), and the response must have at least a Last-Modified header. This requires the query engine to indicate that the query result document can be cached. If the Last-Modified header is present, the query engine should support a conditional GET method (with an If-Modified-Since header) to make caching effective; otherwise it should return an Expires header.

Cache File Size Low Limit. You can set the minimum size for files that will be cached by your Proxy Server. You may want to set a minimum size if you have a fast network connection. If your connection is fast, small files may be retrieved so quickly that the server does not need to cache them. In this instance, you would want to cache only larger files.

Cache File Size High Limit. You can set the maximum size for files that will be cached by your Proxy Server.You may want to set a maximum file size to make sure that large files do not occupy too much of your proxy’s disk space.

Up-to-Date Checking Policy. You can use this option to ensure that the HTTP document is always up-to-date. You can also specify the refresh interval for the Proxy Server.

Expiration Policy. You can set the Expiration Policy using the last modified factor or the explicit expiration information.

Behaviour On Client Interrupt. If a document is only partly retrieved and the client interrupts the data transfer, the proxy has the ability to finish retrieving the document for the purpose of caching it. The proxy’s default is to finish retrieving a document for caching if at least 25 percent of it has already been retrieved. Otherwise, the proxy terminates the remote server connection and removes the partial file.

Behaviour On Failure To Connect To Server. If an up-to-date check on a stale document fails because the origin server is unreachable, you can specify whether the proxy sends the stale document from the cache.

OK. Saves your entries.

Reset. Erases your changes and resets the elements in the page to the values that they contained before your changes.


The Cache Local Hosts Page

The Cache Local Hosts page is used to enable the caching of local hosts.

If a URL requested from a local host lacks a domain name, the Proxy Server will not cache it avoid duplicate caching. For example, if a user requests http://machine/filename.html and http://machine.example.com/filename.html from a local server, both URLs might appear in the cache. Because these files are from a local server, they might be retrieved so quickly that caching the files is not necessary.

However, if your company has servers in many remote locations, you may want to cache documents from all hosts to reduce network traffic and decrease the time needed to access the files.

The following elements are displayed:

Select. Click this button after selecting a resource from the drop-down list.

Regular Expression. Specify a regular expression. For more information, see "Understanding Regular Expressions" in the Proxy Server Administration Guide.

Caching Non-fully Qualified Domain Name Hosts. Enable caching of local hosts by clicking the Enabled button.

OK. Saves your entries.

Reset. Erases your changes and resets the elements in the page to the values that they contained before your changes.


The Set Cache Batch Updates Page

The Set Cache Batch Updates page allows you to pre-load files in a specified web site or do an up-to-date check on documents already in the cache. From the Cache Batch Updates page, you can create, edit, and delete batches of URLs and enable and disable batch updating.

The following elements are displayed:

Create/Select A Batch Update Configuration. You can create, edit, delete, or schedule batches of URLs.

You can actively cache files by specifying files to be batch updated. The Proxy Server allows you to perform an up-to-date check on several files currently in the cache or pre-load multiple files starting from a particular URL.

Select New and Create from the drop-down lists next to Create/Select A Batch Update Configuration. Click OK. A new Set Cache Batch Update page appears.

The following elements are displayed.

Name. Specify a name for the new batch update entry.

Source. Click the radio button for the type of batch update that you want to create. Identify the documents that you want to use in the batch update. There are two options:

Exception(s). Identify any files that you would like to exclude from the batch update.

Resources. Specify the maximum number of simultaneous connections and the maximum number of documents to traverse using any the following options:

Timing. Specify the start and end times for the generation of the batch update. Only one batch update can be active at any time, so it is best to not overlap other batch update configurations.

OK. Saves your entries and returns to the cache batch updates page.

Reset. Erases your changes and resets the elements in the page to the values that they contained before your changes.


Note

You can create, edit, and delete batch update configurations without having batch updates turned on. However, if you want your batch updates to be updated according to the times you set on the Set Cache Batch Updates page, you must turn updates on.


You can edit or delete batch updates using the Set Cache Batch Updates page. You may want to edit a batch update if you need to exclude certain files or want to update the batch more frequently. You may also want to delete a batch update configuration completely.


The View URL Database Page

The View URL Database page is used to view the names and attributes of all recorded cached URLs. The URL information displayed is a list of cached documents grouped by access protocol and site name. You can limit the URLs you view in the list by typing a domain name into the Search field. By accessing this information, you can perform various cache management functions such as expiring and removing documents from the cache.

The following elements are displayed:

Top. Click the Top button to move to the first page of the URL list.

Regenerate. Click the Regenerate button to generate a snapshot of the CacheDB.

Enter URLs To Search For (regular expressions allowed). If you would like to view cache information for a specific URL, enter a URL or regular expression in the Search field and click the Search button.

Caching Information. Lists all the cached URLs.

Ex. Select this option to mark the URL that needs to be expired.

Rm. Select this option to mark the URL that needs to be removed.

Ex/Rem Marked. Click this button to expire or remove the URLs for which the Ex or Rm option has been selected.

Clear Marks. Click this button to clear the selection.

Exp All. Click this button to expire all the URLs that are listed.

Rem All. Click this button to remove all the URLs that are listed.


Note

When you use the Ex or Rm option, the associated file is processed but the changes are not reflected in the snapshot. The snapshot needs to be regenerated for the changes to be visible.



The Configure ICP Page

The Configure ICP page is used to configure proxies, in your ICP neighborhood. You can also add, edit, or delete parent or sibling proxies.

The Internet Cache Protocol (ICP) is an object location protocol that enables caches to communicate with one another. Caches can use ICP to send queries and replies about the existence of cached URLs and about the best locations from which to retrieve those URLs. In a typical ICP exchange, one cache will send an ICP query about a particular URL to all neighboring caches. Those caches will then send back ICP replies that indicate whether or not they contain that URL. If they do not contain the URL, they send back a MISS. If they do contain the URL, they send back a HIT.

The proxies that communicate with each other through ICP are called neighbors. You cannot have more than 64 neighbors in an ICP neighborhood. There are 2 types of neighbors in an ICP neighborhood, parents and siblings. Only parents can access the remote server if no other neighbors have the requested URL. Your ICP neighborhood can have no parents or it can have more than one parent. Any neighbor in an ICP neighborhood that is not a parent is considered a sibling. Siblings cannot retrieve documents from remote servers unless the sibling is marked as the default route for ICP, and ICP uses the default.

You need to configure each neighbor, or local proxy, in your ICP neighborhood.

The following elements are displayed:

Binding Address. Enter the IP address to which the neighbor server will bind.

Port. Enter the port number to which the neighbor server will listen for ICP.

Multicast Address. Enter the multicast address to which the neighbor listens. A multicast address is an IP address to which multiple servers can listen. Using a multicast address allows a proxy to send one query to the network that all neighbors who are listening to that multicast address can see; therefore, eliminating the need to send a query to each neighbor separately. If both a multicast address and bind address are specified for the neighbor, the neighbor uses the bind address to send replies and uses multicast to listen. If neither a bind address or a multicast address is specified, the operating system will decide which address to use to send the data.

Default Route. Enter the name or IP address of the proxy to which the neighbor should route a request when none of the neighboring proxies respond with a hit. If you enter the word origin into this field, or if you leave it blank, the default route will be to the origin server.

Port. Enter the port number of the default route machine that you entered into the Default Route field.

On No Hits, Route Through. Choose the neighbor’s behavior from the drop-down list when none of the siblings in the ICP neighborhood have the requested URL in their caches. You can choose from the following elements:

Server Count. Enter the number of processes that will service ICP requests.

Timeout. Enter the maximum amount of time the neighbor will wait for an ICP response in each round.

OK. Saves your entries.

Reset. Erases your changes and resets the elements in the page to the values that they contained before your changes.

Parent List. Lists all the parent proxies in an ICP neighborhood.

Add. Click this button to add a parent proxy. The ICP Parent page appears. The following elements are displayed:

Delete.To remove parent proxies from an ICP neighborhood, click the radio button next to the parent you want to remove, and click the Delete button.

Edit. To edit parent proxies from an ICP neighborhood, click the radio button next to the parent you want to edit, and click the Edit button. The ICP Parent page appears. Modify the information and click OK.

Sibling List. Lists the sibling proxies that have been added to an ICP neighborhood.

Add. Click this button to add a sibling proxy. The ICP Sibling page appears. The following elements are displayed:

Delete.To remove sibling proxies from an ICP neighborhood, click the radio button next to the sibling you want to remove, and click the Delete button.

Edit. To edit sibling proxies from an ICP neighborhood, click the radio button next to the sibling you want to edit, and click the Edit button. The ICP Sibling page appears. Modify the information and click OK.


The Configure Proxy Array Page

The Configure Proxy Array page is used to create and update the proxy array member list.

You should create and update the proxy array member list from the master proxy of the array only. You only need to create the proxy array member list once, but you can modify it at any time. By creating the proxy array member list, you are generating the PAT file to be distributed to all of the proxies in the array and to any downstream proxies.


Caution

You should only make changes or additions to the proxy array member list through the master proxy in the array. All other members of the array can only read the member list.


The following elements are displayed:

Configuration ID. Specify the internal name for the proxy array configuration.

Array Name. Enter the name of the array.

Reload Configuration Every. Enter the number of minutes between each polling for the PAT file.

Array Enabled. Select this checkbox to enable the array.

Generate PAC. Click this button to manually generate a PAC file from a PAT file. The PAC Generation page appears. The following elements are displayed:

Create. Creates a new proxy array configuration.

Reset. Erases your changes and resets the elements in the page to the values that they contained before your changes.


Note

Be sure to click OK before you begin to add members to the member list.


Member List. This table lists all the members of the proxy array.


Caution

You should only make changes or additions to the proxy array member list through the master proxy in the array. If you modify this list from any other member of the array, all changes will be lost.


Add. Click this button to add a member to the proxy array. The Proxy Array Member page appears. For each member in the proxy array, enter the following and then click OK.

Edit. You can change the information for the members in the proxy array member list. You can only edit the proxy array member list from the master proxy. To edit member list information for any of the members in a proxy array, select the radio button next to the member that you want to edit and click Edit. The Proxy Array Member page appears. Edit the appropriate information and click OK.


Note

If you want your changes to take effect and to be distributed to the members of the proxy array, you need to update the Configuration ID on the Proxy Array Configuration page and click OK. To update the configuration ID, you can simply increase it by one.


Delete. Deleting proxy array members will remove them from the proxy array. You can only delete proxy array members from the master proxy. To delete members of a proxy array, select the radio button from the Member List next to the member that you want to delete. Click the Delete Button.


The Configure Proxy Array Member Page

The Configure Proxy Array Member page is used to configure each member in the proxy array. You cannot configure a member of the array from another member. You also need to configure the master proxy.

The following elements are displayed:

Proxy Array. Indicate whether or not the member needs to poll for the Proxy Array Table (PAT) file by selecting the appropriate radio button. The options include the following:

Parent Array.

Poll Host. Enter the fully qualified host and domain name of the proxy in the parent array that you will poll for the PAT file. This proxy is usually the master proxy of the parent array.

Port. Enter the Port number of the proxy in the parent array that you will poll for the PAT file.

URL. Enter the URL of the PAT file to be polled.

Headers File. Enter the full path name for a file with any special headers that must be sent with the HTTP request for the PAT file such as authentication information.

Parent Array Configuration. Lists the details of the parent array that has been configured.

Delete. Click this button to delete the parent array that has been configured.

OK. Saves your entries.

Reset. Erases your changes and resets the elements in the page to the values that they contained before your changes


The View Parent Array Configuration Page

The View Parent Array Configuration page is used to view information in the PAT file.

If your proxy array is routing through a parent array, you need information about the members of the parent array. This information is sent from the parent array in the form of a PAT file. The information in this PAT file is displayed on the Parent Array Configuration page.



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