HP serviceguard t2808-90006 manual N1, for example Becomes accessible from N2

Disaster Scenarios and Their Handling
Table 4-1	Disaster Scenarios and Their Handling (Continued)
Disaster Scenario		What Happens When	Recovery Process
		This Disaster Occurs
In this case, the package (P1)		When the first failure	Complete the following steps to
runs with RPO-TARGETset to 60		occurs, the package (P1)	initiate a recovery:
seconds.		continues to run on N1 with	1. Restore the FC links between
In this case, initially the		md0 consisting of only S1.
			the data centers. As a result,
package (P1) is running on node		When the second failure
			S2 (/dev/hpdev/mylink-sdf)
N1. P1 uses a mirror md0		occurs, the package fails
			becomes available to N1 and
consisting of S1 (local to node		over to N2 and starts with
			S1 (/dev/hpdev/mylink-sde)
N1, for example		S2.
			becomes accessible from N2.
/dev/hpdev/mylink-sde) and
		When N2 fails, the package	2. To start the package P1 on N1,
S2 (local to node N2). The first
		does not start on node N1
failure occurs when all FC links			check the package log file in
		because a package is
between the two data centers			the package directory and run
		allowed to start only once
fail, causing N1 to lose access to			the commands which will
		with a single disk. You must
S2 and N2 to lose access to S1.			appear to force a package
		repair this failure and both
			start.
Immediately afterwards, a		disks must be synchronized
			When the package starts up on
second failure occurs where		and be a part of the MD
node (N1) goes down because of		array before another failure	N1, it automatically adds S2 back
a power failure.		of same pattern occurs.	into the array and the
After N1 is repaired and		In this failure scenario, only	re-mirroring process is started.
			When re-mirroring is complete,
brought back into the cluster,		S1 is available to P1 on N1,
			the extended distance cluster
package switching of P1 to N1 is		as the FC links between the
			detects and accepts S1 as part of
enabled.		data centers are not
			md0.
		repaired. As P1 started once
IMPORTANT: While it is not a
		with S2 on N2, it cannot
good idea to enable package
		start on N1 until both disks
switching of P1 to N1, it is
		are available.
described here to show recovery
from an operator error.

The FC links between the data centers are not repaired and N2 becomes inaccessible because of a power failure.

94 Chapter 4