Training-high-availability

Concepts

Cluster Resource Agents are told by the Cluster Manager "start up" or "shut down". Virtual IP addresses are managed by the cluster.

Host-based mirroring

Host-based mirroring is done with mdadm. Besides, there is

• log shipping
• synchronous mirroring

Autoyast

install=http://... autoyast=http://...

Migration

A migration in the sense of SAP is a change of OS or DB, but not an upgrade or update.

URLs

• http://www.suse.de/~ug
• http://www.suse.de/~fabian
• http://www.swdist.org
• http://www.easymarketplace.de

IPs

10.31.19.101 sapna1ci
10.31.19.102 sapna1db

Definitions

• SID is NA1
• user na1adm id 2000, group 2000
• user sdb 2001, group 2001
• user sqdna1 id 2002
• ascs gets instance number 00
• ci gets instance number 02
• we use IBM Java 1.4.2

Decisions

• We use a simple stack, that means, if a server goes down, the complete stack switches over to the other node, accepting downtime.

Progress

Start multipath

/etc/init.d/boot.multipath start
/etc/init.d/multipathd start
multipath -ll

fdisk

Make a little partition for the quorum (SFEX) and a large partition for the rest.

mdadm

mdadm.conf:

DEVICE /dev/disk/by-id/scsi-360a98000486e5337524a4f6a4e43542d-part2
ARRAY /dev/md0 level=raid0 num-devices=1 UUID=357d721b:86058e8c:8d746cf9:a620ae3c

mdadm --assemble --config /clusterconf/NA1/mdadm.conf /dev/md0

Create lvm

pvcreate /dev/md0
vgcreate sapvg /dev/md0
lvcreate -L 145G sapdb

Start lvm

vgscan 
vgdisplay
lvdisplay
vgchange -a y sapvg

Mount the vgs

mount /dev/sapvg/usrsap /usr/sap
mount /dev/sapvg/sapdb /sapdb
mount /dev/sapvg/sapmnt /sapmnt

Java

Install java

yast -i java-1.4.2-ibm

SAP

Install

ASCS

./sapinst SAPINST_USE_HOSTNAME sapna1as

Choose Netweaver -> Application Server ABAP -> MaxDB -> High Availability -> ASCS

DB

./sapinst SAPINST_USE_HOSTNAME sapna1db

Choose Netweaver -> Application Server ABAP -> MaxDB -> High Availability -> db instance

CI

./sapinst SAPINST_USE_HOSTNAME sapna1ci

Start

startsap sapna1as
startsap sapna1ci

Cluster

• Test the quorum

/usr/lib64/heartbeat/sfex_stat  /dev/disk/by-id/scsi-360a98000486e5337524a4f6a4e43542d-part1
/usr/lib64/heartbeat/sfex_lock  /dev/disk/by-id/scsi-360a98000486e5337524a4f6a4e43542d-part1
/usr/lib64/heartbeat/sfex_stat  /dev/disk/by-id/scsi-360a98000486e5337524a4f6a4e43542d-part1
/usr/lib64/heartbeat/sfex_unlock  /dev/disk/by-id/scsi-360a98000486e5337524a4f6a4e43542d-part1
/usr/lib64/heartbeat/sfex_stat  /dev/disk/by-id/scsi-360a98000486e5337524a4f6a4e43542d-part1

Example

rx3009:~ # /usr/lib64/heartbeat/sfex_stat  /dev/disk/by-id/scsi-360a98000486e5337524a4f6a4e43542d-part1
control data:
  magic: 0x01, 0x1f, 0x71, 0x7f
  version: 1
  revision: 3
  blocksize: 512
  numlocks: 10
lock data #1:
  status: lock
  count: 16
  nodename: rx3009
status is LOCKED.

rx3010:~ # /usr/lib64/heartbeat/sfex_stat  /dev/disk/by-id/scsi-360a98000486e5337524a4f6a4e43542d-part1
control data:
  magic: 0x01, 0x1f, 0x71, 0x7f
  version: 1
  revision: 3
  blocksize: 512
  numlocks: 10
lock data #1:
  status: lock
  count: 28
  nodename: rx3009
status is UNLOCKED.

• establish passwordless login between the nodes

• write the heartbeat configuration

vi /etc/ha.d/ha.cf

cat /etc/ha.d/authkeys

• propagate it

ha_propagate

Start the cluster configuration

hb_gui

• make sure you have one of the virtual IPs

• start the cluster

/etc/init.d/heartbeat start

• look at the status

crm_mon

• find out what the cluster did recently

cluster_actions

• monitor the cluster

crmmon

Pitfalls

• forgot to have luns before installing
• forgot to use SAPINST_USE_HOSTNAME => had to uninstall ASCS