[Environment configuration] Dorado 6000 V6 (with 50 km remote replication), two Linux hosts, Veritas DMP multipathing, two dual-port 10GE HBAs, and four physical paths between each host and storage. Hosts and storage devices are connected through 10GE switches.
[Symptom] In the Linux + Veritas DMP and iSCSI scenario, the default configuration is used. After a controller is removed, I/Os are restored to zero for 10 seconds. When multiple physical links are faulty, I/Os are restored to zero for more than 7 seconds, which does not meet user requirements. With optimization, I/Os are not zeroed when a single controller is faulty, and I/Os are zeroed for 1 second when multiple physical links are faulty.
[Optimization Solution]
Modify the following parameters in the etc/iscsi/iscsid.cof file:
How long does the node.session.timeo.replacement_timeout = 1 # notify the upper layer of a network fault? Interval for sending ping packets on the node.conn[0].timeo.noop_out_interval = 1 # Timeout interval for the node.conn[0].timeo.noop_out_timeout = 1 # to receive heartbeat packets
Note: After modifying the file, restart the host, re-establish the iSCSI connection, and make the configuration take effect permanently.
