Using SEHA Features in EE¶
Here is a short demonstration how to make use of the Standard Edition High Availability (SEHA) cold failover feature in Enterprise Edition (EE).
I installed a non-RAC Enterprise Edition 19.10 database home on my cluster. Then I created a new database on ACFS:
[oracle@rac1 ~]$ srvctl config database -db si
Database unique name: si
Database name: si
Oracle home: /u01/app/oracle/product/19.3.0/dbhome_non_rac
Oracle user: oracle
Spfile: /acfsmounts/acfs1/SI/spfilesi.ora
Password file:
Domain:
Start options: open
Stop options: immediate
Database role: PRIMARY
Management policy: AUTOMATIC
Server pools:
Disk Groups:
Mount point paths: /acfsmounts/acfs1
Services:
Type: SINGLE
OSDBA group: dba
OSOPER group: oper
Database instance: si
Configured nodes: rac1
CSS critical: no
CPU count: 0
Memory target: 0
Maximum memory: 0
Default network number for database services:
Database is administrator managed
Let us assume I want to utilize some of Standard Edition High Availability (SEHA) features in this database:
[oracle@rac1 ~]$ srvctl modify database -db si -node rac1,rac2
PRCD-1302 : failed to retrieve the node hosting this single-instance database
PRCD-2088 : failed to configure the single instance database si with multiple nodes because it is not a Standard Edition database
[oracle@rac1 ~]$ srvctl relocate database -db si -node rac2
PRKF-1421 : cannot relocate database "si"; invalid database type
As expected, srvctl disallows such operations.
However, the edition check uses the $ORACLE_HOME/lib/libedtn19.a file which I described in the following post: Determining Oracle Database Edition.
It turns out it is enough to copy the standard edition library to make these srvctl commands work:
[oracle@rac1 lib]$ cp libedtn19_std.a libedtn19.a
[oracle@rac1 ~]$ srvctl modify database -db si -node rac1,rac2
[oracle@rac1 ~]$ srvctl config database -db si
Database unique name: si
Database name: si
Oracle home: /u01/app/oracle/product/19.3.0/dbhome_non_rac
Oracle user: oracle
Spfile: /acfsmounts/acfs1/SI/spfilesi.ora
Password file:
Domain:
Start options: open
Stop options: immediate
Database role: PRIMARY
Management policy: AUTOMATIC
Server pools:
Disk Groups:
Mount point paths: /acfsmounts/acfs1
Services:
Type: SINGLE
OSDBA group: dba
OSOPER group: oper
Database instance: si
Configured nodes: rac1,rac2
CSS critical: no
CPU count: 0
Memory target: 0
Maximum memory: 0
Default network number for database services:
Database is administrator managed
My clusterware resources before doing the srvctl relocate database command:
[grid@rac2 ~]$ crsctl stat res -t
--------------------------------------------------------------------------------
Name Target State Server State details
--------------------------------------------------------------------------------
Local Resources
--------------------------------------------------------------------------------
ora.DATA.VOLUME1.advm
ONLINE ONLINE rac1 STABLE
ONLINE ONLINE rac2 STABLE
ora.LISTENER.lsnr
ONLINE ONLINE rac1 STABLE
ONLINE ONLINE rac2 STABLE
ora.chad
ONLINE ONLINE rac1 STABLE
ONLINE ONLINE rac2 STABLE
ora.data.volume1.acfs
ONLINE ONLINE rac1 mounted on /acfsmoun
ts/acfs1,STABLE
ONLINE ONLINE rac2 mounted on /acfsmoun
ts/acfs1,STABLE
ora.net1.network
ONLINE ONLINE rac1 STABLE
ONLINE ONLINE rac2 STABLE
ora.ons
ONLINE ONLINE rac1 STABLE
ONLINE ONLINE rac2 STABLE
ora.proxy_advm
ONLINE ONLINE rac1 STABLE
ONLINE ONLINE rac2 STABLE
--------------------------------------------------------------------------------
Cluster Resources
--------------------------------------------------------------------------------
ora.ASMNET1LSNR_ASM.lsnr(ora.asmgroup)
1 ONLINE ONLINE rac1 STABLE
2 ONLINE ONLINE rac2 STABLE
ora.DATA.dg(ora.asmgroup)
1 ONLINE ONLINE rac1 STABLE
2 ONLINE ONLINE rac2 STABLE
ora.GRID.dg(ora.asmgroup)
1 ONLINE ONLINE rac1 STABLE
2 ONLINE ONLINE rac2 STABLE
ora.LISTENER_SCAN1.lsnr
1 ONLINE ONLINE rac2 STABLE
ora.LISTENER_SCAN2.lsnr
1 ONLINE ONLINE rac1 STABLE
ora.LISTENER_SCAN3.lsnr
1 ONLINE ONLINE rac1 STABLE
ora.asm(ora.asmgroup)
1 ONLINE ONLINE rac1 Started,STABLE
2 ONLINE ONLINE rac2 Started,STABLE
ora.asmnet1.asmnetwork(ora.asmgroup)
1 ONLINE ONLINE rac1 STABLE
2 ONLINE ONLINE rac2 STABLE
ora.cvu
1 ONLINE ONLINE rac1 STABLE
ora.qosmserver
1 ONLINE ONLINE rac1 STABLE
ora.rac1.vip
1 ONLINE ONLINE rac1 STABLE
ora.rac2.vip
1 ONLINE ONLINE rac2 STABLE
ora.scan1.vip
1 ONLINE ONLINE rac2 STABLE
ora.scan2.vip
1 ONLINE ONLINE rac1 STABLE
ora.scan3.vip
1 ONLINE ONLINE rac1 STABLE
ora.si.db
1 ONLINE ONLINE rac1 Open,HOME=/u01/app/o
racle/product/19.3.0
/dbhome_non_rac,STAB
LE
--------------------------------------------------------------------------------
Running srvctl relocate database:
[oracle@rac1 ~]$ srvctl relocate database -db si -node rac2
[oracle@rac1 ~]$ srvctl status database -db si
Instance si is running on node rac2
Clusterware also restarts that database on a working node in case the node it was running on fails.
To test that, I initiated a kernel panic on the rac1 node where my database was running:
[root@rac1 ~]# echo c > /proc/sysrq-trigger
After a while, the database was started on the other node:
[grid@rac2 ~]$ crsctl stat res -t
--------------------------------------------------------------------------------
Name Target State Server State details
--------------------------------------------------------------------------------
Local Resources
--------------------------------------------------------------------------------
ora.DATA.VOLUME1.advm
ONLINE ONLINE rac2 STABLE
ora.LISTENER.lsnr
ONLINE ONLINE rac2 STABLE
ora.chad
ONLINE ONLINE rac2 STABLE
ora.data.volume1.acfs
ONLINE ONLINE rac2 mounted on /acfsmoun
ts/acfs1,STABLE
ora.net1.network
ONLINE ONLINE rac2 STABLE
ora.ons
ONLINE ONLINE rac2 STABLE
ora.proxy_advm
ONLINE ONLINE rac2 STABLE
--------------------------------------------------------------------------------
Cluster Resources
--------------------------------------------------------------------------------
ora.ASMNET1LSNR_ASM.lsnr(ora.asmgroup)
1 ONLINE OFFLINE STABLE
2 ONLINE ONLINE rac2 STABLE
ora.DATA.dg(ora.asmgroup)
1 ONLINE OFFLINE STABLE
2 ONLINE ONLINE rac2 STABLE
ora.GRID.dg(ora.asmgroup)
1 ONLINE OFFLINE STABLE
2 ONLINE ONLINE rac2 STABLE
ora.LISTENER_SCAN1.lsnr
1 ONLINE ONLINE rac2 STABLE
ora.LISTENER_SCAN2.lsnr
1 ONLINE ONLINE rac2 STABLE
ora.LISTENER_SCAN3.lsnr
1 ONLINE ONLINE rac2 STABLE
ora.asm(ora.asmgroup)
1 ONLINE OFFLINE STABLE
2 ONLINE ONLINE rac2 Started,STABLE
ora.asmnet1.asmnetwork(ora.asmgroup)
1 ONLINE OFFLINE STABLE
2 ONLINE ONLINE rac2 STABLE
ora.cvu
1 ONLINE ONLINE rac2 STABLE
ora.qosmserver
1 ONLINE ONLINE rac2 STABLE
ora.rac1.vip
1 ONLINE INTERMEDIATE rac2 FAILED OVER,STABLE
ora.rac2.vip
1 ONLINE ONLINE rac2 STABLE
ora.scan1.vip
1 ONLINE ONLINE rac2 STABLE
ora.scan2.vip
1 ONLINE ONLINE rac2 STABLE
ora.scan3.vip
1 ONLINE ONLINE rac2 STABLE
ora.si.db
1 ONLINE ONLINE rac2 Open,HOME=/u01/app/o
racle/product/19.3.0
/dbhome_non_rac,STAB
LE
--------------------------------------------------------------------------------
I am unsure about the exact repercussions of that library change.
Obviously srvctl uses libedtn19.a as it was demonstrated above.
Whether or not it can cause any adverse effects - I do not know.
Evidently such configuration is anything but supported by Oracle. The officially supported way of making EE cold failover configuration on non-RAC environments uses custom Clusterware resources, which I personally find clunky. I wish those SEHA features were available on EE, but it is not the case at present.