Disaster Scenarios and Their Handling

Table 4-1

Disaster Scenarios and Their Handling (Continued)

 

 

 

 

Disaster Scenario

What Happens When

Recovery Process

This Disaster Occurs

 

 

 

 

 

 

A package (P1) is running on a

The package (P1) continues

Once you restore power to S1, or

node (Node 1). The package uses

to run on Node 1 with the

restore the FC links to S1, the

a mirror (md0) that consists of

mirror that consists of only

corresponding mirror half of S1

two storage components - S1

S2.

(/dev/hpdev/mylink-sde) is

(local to Node 1 -

 

 

accessible from Node 1. To make

/dev/hpdev/mylink-sde) and

 

the restored mirrored half part of

S2 (local to Node 2).

 

 

the MD array, complete the

Access to S1 is lost from both

 

following procedure:

 

 

nodes, either due to power

 

1. Run the following command to

failure to S1 or loss of FC links

 

remove the mirrored half from

to S1.

 

 

 

 

the array:

 

 

 

 

 

 

# mdadm --remove /dev/md0

 

 

 

/dev/hpdev/mylink-sde

 

 

 

2. Run the following command to

 

 

 

add the mirrored half to the

 

 

 

array:

 

 

 

# mdadm --add /dev/md0

 

 

 

/dev/hpdev/mylink-sde

 

 

 

The re-mirroring process is

 

 

 

initiated. When it is complete, the

 

 

 

extended distance cluster detects

 

 

 

the added mirror half and accepts

 

 

 

S1 as part of md0.

 

 

 

 

Chapter 4

87