High availability solution for LOW cost! 1

[soccercoach]

I am in need of a solution that would allow a production rp3410 hpux server a method to fail over to another rp3410 without spending much (as in $0) money. I have an MSA1000 SAN that houses an Oracle database. The I/O to this Oracle database is controlled by one rp3410 hpux server (I'll call him serverA). I want to be able, in the event the production server dies, to manually failover to another rp3410 (called serverB). What I am struggling with is how to point serverB to the space on the SAN that houses the Oracle database. I know that Serviceguard give you that capability but I have no money to spend on it. I am seeking some suggestions as to the best way to ensure I can keep access to the database in the event of a server crash.
Please accept my thanks in advance for any ideas you may have!

 

[Chacalinc]

...is how to point serverB to the space on the SAN that houses the Oracle database.

[tt]man vgchange
man vgexport
man vgimport [/tt]

you have to share the LUNs, the problem with this configuration is the security, ServiceGuard prevents you to mount a volume group (VG) from the another server when serverA has the VG mounted. Quite risky. (cheap is expensive)

Anyway, you need to have configured all VGs in both servers with all the access. In the event you need to failover you should issue:

From ServerA (if you can):
umount /all_mount_points
vgchange -a n /dev/vgXXX

From ServerB:
vgchange -a y /dev/vgXXX
fsck /dev/vgXXX/lvolXXX (may be)
mount /all_mount_points

As you can see it is simple, but risky! ServiceGuard make all the job for you. (well, it startup the oracle, check consistensy, other P )

Cheers.


Chacal, Inc.

 

[soccercoach]

Chacalinc,

Is it possible to use SAM to configure the Volume Groups I need on serverB? I do see how it would be very risky for both servers to see that space! I want to only do this if serverA fails and cannot be brought back to life within the Service Level Agreement time frame. Sort of a "last resort"!

Thanks!

 

[Chacalinc]

ok, I understand...

Is it possible to use SAM to configure the Volume Groups I need on serverB?

I recommend you to make all the steps manually, just because you need to know what's going on... (remember it is a crisis). In order to import all the VGs in serverB you need to get the maps (of the VG) from ServerA:

[tt]vgexport -p -m vgXXX.map /dev/vgXXX [/tt]

(don't remember the exact parameter, so man vgexport || -p if my memory serves me, is for "preview" only and not erase the VG definition)

then copy the .map files to serverB and, with access to all LUNs, import the VG:

[tt]mkdir /dev/vgXXX
mknod /dev/vgXXX/group c 64 0xHH0000
vgimport -m vgXXX.map /dev/vgXXX /dev/dsk/cXtXdX
vgchange -a y /dev/vgXXX[/tt]


Cheers.

Chacal, Inc.

 

[soccercoach]

Thanks so much for this info. I will give it try! I really appreciate you taking the time to help!