ASM 12c, OCR and voting devices II

I finished the installation of 12c cluster and noticed that I haven’t been asked for voting and registry devices as was previously the case. I had to create a single disk group. John Franklin, from LinkedIn RAC SIG suggested running ocrcheck command, so I did:

[grid@rac1 ~]$ ocrcheck -details
Status of Oracle Cluster Registry is as follows :
Version : 4
Total space (kbytes) : 409568
Used space (kbytes) : 1612
Available space (kbytes) : 407956
ID : 1368218241
Device/File Name : +DATA/scan11/OCRFILE/registry.255.886021581
Device/File integrity check succeeded

Device/File not configured

Device/File not configured

Device/File not configured

Device/File not configured

Cluster registry integrity check succeeded

Logical corruption check bypassed due to non-privileged user

[grid@rac1 ~]$

So OCR file is still there, only lumped as a single file in the disk group created during the installation. So, let’s see what else is there:

ASMCMD> ls +DATA
ASM/
ORCL/
_MGMTDB/
orapwasm
scan11/

ORCL is the name of my Oracle 11.2.0.4 database, scan11 is the cluster name. Registry is precisely where ocrcheck said it would be:

ASMCMD> ls scan11
ASMPARAMETERFILE/
OCRFILE/
ASMCMD> ls scan11/OCRFILE
REGISTRY.255.886021581
ASMCMD>

What in the world is MGMTDB? Turns out that it is pretty well documented:

Mike Dietrich’s blog

Management database contains cluster health information and is a full fledged Oracle database which uses 4.5GB:

I finished the installation of 12c cluster and noticed that I haven’t been asked for voting and registry devices as was previously the case. I had to create a single disk group. John Franklin, from LinkedIn RAC SIG suggested running ocrcheck command, so I did:

[grid@rac1 ~]$ ocrcheck -details
Status of Oracle Cluster Registry is as follows :
Version : 4
Total space (kbytes) : 409568
Used space (kbytes) : 1612
Available space (kbytes) : 407956
ID : 1368218241
Device/File Name : +DATA/scan11/OCRFILE/registry.255.886021581
Device/File integrity check succeeded

Device/File not configured

Device/File not configured

Device/File not configured

Device/File not configured

Cluster registry integrity check succeeded

Logical corruption check bypassed due to non-privileged user

[grid@rac1 ~]$

So OCR file is still there, only lumped as a single file in the disk group created during the installation. So, let’s see what else is there:

ASMCMD> ls +DATA
ASM/
ORCL/
_MGMTDB/
orapwasm
scan11/

ORCL is the name of my Oracle 11.2.0.4 database, scan11 is the cluster name. Registry is precisely where ocrcheck said it would be:

ASMCMD> ls scan11
ASMPARAMETERFILE/
OCRFILE/
ASMCMD> ls scan11/OCRFILE
REGISTRY.255.886021581
ASMCMD>

What in the world is MGMTDB? Turns out that it is pretty well documented:

Mike Dietrich’s blog

Management database contains cluster health information and is a full fledged Oracle database which uses 4.5GB:

ASMCMD> du _MGMTDB
Used_MB Mirror_used_MB
4365 4365
ASMCMD>

Ti instance is, of course running:

[grid@rac1 ~]$ ps -ef|grep smon
grid 3579 1 0 10:02 ? 00:00:00 asm_smon_+ASM2
root 4818 1 0 10:02 ? 00:00:17 /app/grid/12.1.0/bin/osysmond.bi
grid 5388 1 0 10:03 ? 00:00:00 mdb_smon_-MGMTDB

So, let’s see what’s in there:

[grid@rac1 ~]$ export ORACLE_SID=”-MGMTDB”
[grid@rac1 ~]$ sqlplus / as sysdba

SQL*Plus: Release 12.1.0.2.0 Production on Mon Jul 27 10:37:43 2015

Copyright (c) 1982, 2014, Oracle. All rights reserved.
Connected to:
Oracle Database 12c Enterprise Edition Release 12.1.0.2.0 – 64bit Production
With the Partitioning, Automatic Storage Management and Advanced Analytics options

SQL> select username from dba_users;

USERNAME
——————————————————————————–
ANONYMOUS
DBSNMP
WMSYS
XDB
APPQOSSYS
GSMADMIN_INTERNAL
GSMCATUSER
SYSBACKUP
OUTLN
DIP
SYSDG

USERNAME
——————————————————————————–
ORACLE_OCM
SYSKM
XS$NULL
GSMUSER
AUDSYS
SYSTEM
SYS

18 rows selected.

SQL> alter session set current_schema=GSMADMIN_INTERNAL;

Session altered.

SQL> desc database
Name Null? Type
—————————————– ——– —————————-
NAME NOT NULL VARCHAR2(30)
POOL_NAME VARCHAR2(30)
REGION_NUM NUMBER
GSM_PASSWORD NOT NULL VARCHAR2(30)
CONNECT_STRING NOT NULL VARCHAR2(256)
DATABASE_NUM NOT NULL NUMBER
STATUS NOT NULL CHAR(1)
SCAN_ADDRESS VARCHAR2(256)
ONS_PORT NUMBER
NUM_ASSIGNED_INSTANCES NOT NULL NUMBER
SRLAT_THRESH NUMBER
CPU_THRESH NUMBER
VERSION VARCHAR2(30)
DB_TYPE CHAR(1)
ENCRYPTED_GSM_PASSWORD RAW(2000)

SQL> select name,version,db_type from database;

no rows selected

SQL> select * from database;

no rows selected

SQL> select * from verify_history
2 /

no rows selected

SQL>

So, nothing is in there yet. I will have to follow the documentation and set up monitoring and diagnostic data collection.  I am slightly worried because another full fledged EE Oracle instance is added to my RAC nodes, thereby increasing CPU and memory consumption. On the other hand, the metrics described in the manual page looks very useful. A system monitoring repository can be a treasure trove of the information. My feelings are mixed, let’s wait and see.

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About mgogala

I am a consultant with an extensive Oracle DBA experience. I have worked on very large databases. I have worked with OPS and RAC since its inception.I am also a published book writer, having published two books about PHP. This blog is about the challenges and adventures in my professional life. Sorry, no family pictures here.
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