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Determining path status for your HA pair

If you want to remove a module from your HA pair, you need to know whether the path you will disrupt is redundant. You can use the storage show disk -p command to indicate whether the disks have redundant paths.

About this task

If the disks have redundant paths, you can remove the module without interfering with the storage system’s ability to serve data. However, if that module provides the only path to any of the disks in your HA pair, you must take action to ensure that you do not incur system downtime.

Step

  1. Use the storage show disk -p command at your system console.

    This command displays the following information for every disk in the HA pair:

    • Primary port
    • Secondary port
    • Disk shelf
    • Bay

Examples for configurations with and without redundant paths

The following example shows what the storage show disk -p command output might look like for a redundant-path HA pair consisting of FAS systems:
PRIMARY PORT SECONDARY PORT SHELF BAY
------- ---- --------- ---- ----- ---
0c.112   A    0b.112    B     7    0 
0b.113   B    0c.113    A     7    1 
0b.114   B    0c.114    A     7    2 
0c.115   A    0b.115    B     7    3
0c.116   A    0b.116    B     7    4 
0c.117   A    0b.117    B     7    5 
0b.118   B    0c.118    A     7    6 
0b.119   B    0c.119    A     7    7 
0b.120   B    0c.120    A     7    8 
0c.121   A    0b.121    B     7    9 
0c.122   A    0b.122    B     7   10
0b.123   B    0c.123    A     7   11
0c.124   A    0b.124    B     7   12
0b.125   B    0c.125    A     7   13

Notice that every disk (for example, 0c.112/0b.112) has two ports active: one for A and one for B. The presence of the redundant path means that you do not need to fail over one system before removing modules from the system.

Attention: Make sure that every disk has two paths. Even in an HA pair configured for redundant paths, a hardware or configuration problem can cause one or more disks to have only one path. If any disk in your HA pair has only one path, you must treat that loop as if it were in a single-path HA pair when removing modules.

The following example shows what the storage show disk -p command output might look like for an HA pair consisting of FAS systems that do not use redundant paths:

filer1> storage show disk -p
PRIMARY PORT SECONDARY PORT SHELF BAY
------- ---- --------- ---- ----- ---
5b.16     B                   1    0 
5b.17     B                   1    1 
5b.18     B                   1    2 
5b.19     B                   1    3 
5b.20     B                   1    4 
5b.21     B                   1    5 
5b.22     B                   1    6 
5b.23     B                   1    7 
5b.24     B                   1    8 
5b.25     B                   1    9 
5b.26     B                   1   10 
5b.27     B                   1   11 
5b.28     B                   1   12 
5b.29     B                   1   13 

For this HA pair, there is only one path to each disk. This means that you cannot remove a module from the configuration, thereby disabling that path, without first performing a takeover.