EDirectory Database Cache Test

The most significant setting that affects eDirectory performance is the cache. With eDirectory 8.5 or later, you can specify a block cache limit and an entry cache limit. The block cache caches only physical blocks from the database. The entry cache caches logical entries from the database. The caching of entries reduces the processing time required to instantiate entries in memory from the block cache.

This test monitors the block and entry caches of every eDirectory database, and reports whether they are efficiently utilized or not.

Target of the test : An eDirectory server

Agent deploying the test : An internal agent

Outputs of the test : One set of results for every eDirectory database being monitored.

Configurable parameters for the test
Parameter Description

Test Period

How often should the test be executed.

Host

The IP address of the host for which this test is to be configured.

SNMPPort

The port at which the monitored target exposes its SNMP MIB; The default value is 161.

SNMPVersion

By default, the eG agent supports SNMP version 1. Accordingly, the default selection in the SNMPversion list is v1. However, if a different SNMP framework is in use in your environment, say SNMP v2 or v3, then select the corresponding option from this list.

SNMPCommunity

The SNMP community name that the test uses to communicate with the firewall. This parameter is specific to SNMP v1 and v2 only. Therefore, if the SNMPVersion chosen is v3, then this parameter will not appear.

UserName

This parameter appears only when v3 is selected as the SNMPVersion. SNMP version 3 (SNMPv3) is an extensible SNMP Framework which supplements the SNMPv2 Framework, by additionally supporting message security, access control, and remote SNMP configuration capabilities. To extract performance statistics from the MIB using the highly secure SNMP v3 protocol, the eG agent has to be configured with the required access privileges – in other words, the eG agent should connect to the MIB using the credentials of a user with access permissions to be MIB. Therefore, specify the name of such a user against this parameter. 

Context

This parameter appears only when v3 is selected as the SNMPVersion. An SNMP context is a collection of management information accessible by an SNMP entity. An item of management information may exist in more than one context and an SNMP entity potentially has access to many contexts. A context is identified by the SNMPEngineID value of the entity hosting the management information (also called a contextEngineID) and a context name that identifies the specific context (also called a contextName). If the Username provided is associated with a context name, then the eG agent will be able to poll the MIB and collect metrics only if it is configured with the context name as well. In such cases therefore, specify the context name of the Username in the Context text box.  By default, this parameter is set to none.

AuthPass

Specify the password that corresponds to the above-mentioned Username. This parameter once again appears only if the SNMPversion selected is v3.

Confirm Password

Confirm the AuthPass by retyping it here.

AuthType

This parameter too appears only if v3 is selected as the SNMPversion. From the Authtype list box, choose the authentication algorithm using which SNMP v3 converts the specified username and password into a 32-bit format to ensure security of SNMP transactions. You can choose between the following options:

  • MD5 – Message Digest Algorithm
  • SHA – Secure Hash Algorithm

EncryptFlag

This flag appears only when v3 is selected as the SNMPversion. By default, the eG agent does not encrypt SNMP requests. Accordingly, the this flag is set to No by default. To ensure that SNMP requests sent by the eG agent are encrypted, select the Yes option. 

EncryptType

If this EncryptFlag is set to Yes, then you will have to mention the encryption type by selecting an option from the EncryptType list. SNMP v3 supports the following encryption types:

  • DES – Data Encryption Standard
  • AES – Advanced Encryption Standard

EncryptPassword

Specify the encryption password here.

Confirm Password

Confirm the encryption password by retyping it here.

Timeout

Specify the duration (in seconds) within which the SNMP query executed by this test should time out in this text box. The default is 10 seconds.

Data Over TCP

By default, in an IT environment, all data transmission occurs over UDP. Some environments however, may be specifically configured to offload a fraction of the data traffic – for instance, certain types of data traffic or traffic pertaining to specific components – to other protocols like TCP, so as to prevent UDP overloads. In such environments, you can instruct the eG agent to conduct the SNMP data traffic related to the monitored target over TCP (and not UDP). For this, set this flag to Yes. By default, this flag is set to No.

Measurements made by the test
Measurement Description Measurement Unit Interpretation

EDirectory database size

Indicates the current size of the eDirectory database.

KB

 

Database block size

Indicates the current block size of the eDirectory database.

KB

 

Database entry current size

Indicates the current entry cache size.

KB

With an entry cache and a block cache, the total available memory for caching should be shared between the two caches. If the server you are installing eDirectory on does not have a replica, the default is a hard memory limit of 16 MB, with 8 MB for block cache and 8 MB for entry cache. If the server contains a replica, the default is a dynamically adjusting limit. The dynamically adjusting limit causes eDirectory to periodically adjust its memory consumption in response to the ebb and flow of memory consumption by other processes. You specify the limit as a percentage of available physical memory. Using this percentage, eDirectory recalculates a new memory limit at fixed intervals. The new memory limit is the percentage of physical memory available at the time.  Along with the percentage, you can set a maximum and minimum threshold. The threshold is the number of bytes that eDirectory will adjust to. It can be set as either the number of bytes to use or the number of bytes to leave available. The minimum threshold default is 16 MB. The maximum threshold default is 4 GB. With the dynamically adjusting limit, you also specify the interval length. The default interval is 15 seconds. The shorter the interval, the more the memory consumption is based on current conditions.

Database block current size

Indicates the current block cache size.

KB

Database entry items cached

Indicates the number of entries in the entry cache, currently.

Number

An Entry cache is most useful for operations that browse the eDirectory tree by reading through entries, such as name resolution. A well-sized entry cache thus speeds up the retrieval of entries referenced from an index. Therefore, ideally, the value of this measure should be high.

Database block items cached

Indicates the number of blocks in the block cache, currently.

Number

A well-sized block cache is most useful for update operations and can speed up index searching. A very low number of blocks in this cache could considerably slow-down key eDirectory operations. Therefore, ideally, this value should be high.

The more blocks and entries that can be cached, the better the overall performance will be.

Database entry cache hits

Indicates the percentage of database hits that were served by the entries in the entry cache.

Percent

Typically, a 1:1 ratio for block cache, and a 1:2 or 1:4 ratio for the entry cache is desired. Anything lesser indicates that the entry and block caches are unable to fulfill most of the requests to the eDirectory server. This happens when an adequate number of blocks/entries is not cached.

Badly-sized caches escalate direct disk accesses and processing overheads as well.

The ideal is to cache the entire database in both the entry and block caches, although this is not possible for extremely large databases.

DB block cache hits

Indicates the percentage of database hits that were serviced by the blocks in the block cache.

Percent