IBM TotalStorage DS300 Best Practices Manual page 445

Failover when network path from eth0 to switch fails
"Failover in case of a controller failover in the DS300" on page 429
Failover when network path from eth0 to switch fails
In this test, the network cable from eth0 to the switch is unplugged. IO is created
during the test with the following command:
dd if=/dev/urandom of=/mnt/danube-disk1/10GBfile bs=1M count=10000
Example 7-13 shows logging information in /var/log/messages during the outage
of eth0.
Example 7-13 /var/log/messages during outage of eth0
Aug 3 13:23:20 danube kernel: tg3: eth0: Link is down.
Aug 3 13:23:29 danube kernel: iSCSI: 10 second timeout expired for session iscsi bus 0 target
id 2, rx 710007, ping 715006, now 720007
Aug 3 13:23:29 danube kernel: iSCSI: session iscsi bus 0 target id 2 iscsi_xmit_task -
xmit_data failed to send 65584 bytes,rc 54928
[...]
Aug 3 13:23:29 danube kernel: iSCSI: session iscsi bus 0 target id 2 to danube-disk1 dropped
Aug 3 13:23:29 danube kernel: iSCSI: bus 0 target 2 trying to establish session to portal 0,
address 192.168.1.61 port 3260 group 1
Aug 3 13:23:34 danube kernel: iSCSI: Requested ioctl not found
Aug 3 13:23:39 danube kernel: iSCSI: session iscsi bus 0 target id 2 replacement timed after
10 seconds, drop 720007, now 730007, failing all commands
Aug 3 13:23:39 danube multipathd: 8:16: readsector0 checker reports path is down
Aug 3 13:23:39 danube multipathd: checker failed path 8:16 in map 20003390012f2c829
Aug 3 13:23:39 danube multipathd: devmap event (2) on 20003390012f2c829
Aug 3 13:23:39 danube kernel: Device sdb not ready.
Aug 3 13:23:39 danube kernel: end_request: I/O error, dev sdb, sector 577864
Aug 3 13:23:39 danube kernel: device-mapper: dm-multipath: 8:16 (#577872): IO error - error:
-5 - bi_rw: 9 - bi_flags: 10 - bi_error: 00000000
Aug 3 13:23:39 danube kernel: device-mapper: dm-multipath: Failing path 8:16
Aug 3 13:23:39 danube kernel: device-mapper: dm-multipath: 8:16 (#577864): Requeued sector as
#1
Aug 3 13:23:39 danube kernel: device-mapper: dm-multipath: 8:16 (#577880): IO error - error:
-5 - bi_rw: 9 - bi_flags: 10 - bi_error: 00000000
Aug 3 13:23:39 danube kernel: device-mapper: dm-multipath: 8:16 (#577872): Requeued sector as
#2
[...]
The multipath -l command shows the new situation. The remaining path via
eth1 is used to continue IO operations.
Example 7-14 multipath -l output after eth0 outage
danube:~ # multipath -l
Chapter 7. TotalStorage DS300 installation
427