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HP Hitachi Dynamic Link Manager Software User Manual

Page 355

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4. HDLM Operation

331

Figure 4-1: Overview of the Period Required to Respond to an Application's I/

O Request

As shown in the preceding diagram, when an HDLM device has two paths (SCSI

devices), the maximum period of time required to respond to the application's I/

O request is n1 + n2 seconds; where n1 indicates the timeout value specified for

the path that uses SCSI device A, and n2 indicates the timeout value specified for

the path that uses SCSI device B.

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When using HDLM in a cluster environment, a node in the cluster may fail over

before the path completes failover. To avoid this, when you set up the failover

timeout value for the node by using cluster software, make sure that you specify

a period longer than the response time that is calculated as described in the

preceding note.

„

If a path error occurs while creating a file system, or formatting, or executing

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