VSP Channel Adapters Test

A Hitachi VSP may comprise of multiple Channel adapters. The Channel adapter (CHA) processes a command from a host or other storage system to a local storage system and controls data transfer to the Hitachi VSP. The host and other storage system are connected to a fibre port on the CHA via the fibre channel. Sending and receiving commands to and from another storage system via the channel adapter enables data copy and backup between storages. For the data to be copied swiftly to the storage of the Hitachi VSP, it is essential for the Channel adapters to respond to the requests in a quick manner. If the Channel adapters are busy or unable to process the requests as and when the requests are received, then the data backup between the storage systems may not synchronize leading to data loss which inturn would result in critical failures. To avoid such critical failures, it is essential for the administrators to monitor each Channel adapter of the target Hitachi VSP and figure out the responsiveness and utilization of the Channel adapters. The VSP Channel Adapters Test helps administrators to proactively determine the responsiveness of the channel adapters.

This test monitors the usage and responsiveness of each channel adapter, and reveals over-utilized channel adapters (if any).

Target of the test : A Hitachi VSP storage device

Agent deploying the test : A remote agent

Outputs of the test : One set of results for every channel adapter on the target Hitachi VSP device being monitored

Configurable parameters for the test
  1. TEST PERIOD - How often should the test be executed
  2. HOST - The host for which the test is to be configured.
  3. PORT - The port at which the device listens. By default, this is set to NULL.

  4. USERID and PASSWORD – To extract metrics from the target storage device, the eG agent should be configured with the credentials of a special user account, which is specifically created for use with the Java export utility. This user account should fulfill the following conditions:

    • Should not possess the ‘write’ permission;
    • Can be of any user type; however, to ensure that the eG agent collects statistics pertaining to all storage partitions, it is recommended that this user is of type storage administrator;

    Specify the credentials of such a user in the USERID and PASSWORD text boxes.

  5. CONFIRM PASSWORD - Confirm the password by retyping it here.
  6. TIMEOUT - Specify the time duration (in seconds) beyond which this test should time out in the TIMEOUT text box. The default is 3 seconds.
Measures made by the test:
Measurement Description Measurement Unit Interpretation

Channel adapter usage:

Indicates the percentage of time for which this channel adapter was in use.

Percent

A high value or a value close to 100% is indicative of excessive usage of the channel processor. By comparing the value of this measure across adapters, you can accurately detect imbalances in load distribution, and rapidly identify the affected channel adapters. To ensure that load is balanced, you might want to consider the following:

  • Install additional CHAs, or;
  • Move devices defined on already overloaded ports to ports with CHPs that are less utilized, so as to balance front-end usage;

Data traffic:

Indicates the rate at which data is transferred over this channel adapter port.

KB/Sec

 

Response time:

Indicates the responsiveness of this channel adapter port to read-write requests.

Microseconds

Ideally, the value of this measure should be low. If the value of this measure is very high or is increasing steadily, then, you might want to check whether the I/O operations rate measure too reports a high value. If so, it is a clear indication that since the I/O activity is high, the hosts are taking a longer time to access the disks, thereby increasing the response time.