Can I adjust the number of multi-write operations sent across the network?

Document ID : KB000053549
Last Modified Date : 14/02/2018
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Description

To prevent network flooding, CA Directory has a throttling mechanism within the multiwrite replication component. This is particularly useful where network links are unreliable. This techdoc explains how to configure this new setting within CA Directory.

Solution

To prevent network flooding, CA Directory has a throttling mechanism within the multiwrite replication component. This is particularly useful where network links are unreliable.

Multiwrite will send a specific number of multiwrite operations and then wait for a response from the replication peer DSA.

This mw operation threshold is normally set at 10. For most implementations the default of 10 is quite sufficient and should not be changed unless there is a specific reason.

The command below enables this threshold to be changed:

set multi-write-outstanding-ops = <num>;

This command is principally to allow the directory administrator to tune multiwrite throughput and performance.

Adding the above command increases the threshold of outstanding multiwrite operations, before multiwrite waits for a response.

Example Scenario:

  • To set the number of entries sent via multiwrite without waiting for a response, to a larger number:

    set multi-write-outstanding-ops = 100;

Note that this may not itself increase multiwrite throughput.

This command should be added to the multiwrite DSAs "limits" file. Please stop and restart the DSA after the parameter has been saved to the DSAs configuration file.

Please Note:

The default multiwrite operation threshold should only be changed by someone with advanced network knowledge and only if the speed of the replication is of concern.

In normal circumstances, changing this parameter will have little effect. However, if there is a problem with multiwrite performance over latent links, changing this setting to a higher value may improve the situation.