Installing and Configuring ASMLIb on Oracle Linux 7

Hi all!
For those are familiar with RHEL/OEL 4 and 5, there is some differences to start ASMLib on OEL 6 and 7.

spanner.png
So, a quick guide to install (done on OEL 7), start and configure:

1. Install the ASMLib kernel module package as root using the following command:

yum install kmod-oracleasm

2. Install the ASMLib library package and utilities package

yum install oracleasm-support oracleasmlib oracleasm-`uname -r`

It’s possible some package to not found. For example:

No package oracleasmlib available.

So, you can download rpm libs from here and install via rpm:

[root@dbsrv01 oracle]# rpm -Uvh ~/oracleasmlib-2.0.12-1.el6.x86_64.rpm
Preparing...                          ################################# [100%]
Updating / installing...
1:oracleasmlib-2.0.12-1.el6        ################################# [100%]

Ok, now, lets configure/start services:

[root@dbsrv01 ~]# /etc/init.d/oracleasm configure

Nothing happen? Ok, let’s try to start it:

[root@dbsrv01 ~]# /etc/init.d/oracleasm start
Starting oracleasm (via systemctl):  Job for oracleasm.service failed because the control process exited with error code. See "systemctl status oracleasm.service" and "journalctl -xe" for details.
[FAILED]

Hmmm… Are these commands correct?

[root@dbsrv01 ~]# /etc/init.d/oracleasm
Usage: /etc/init.d/oracleasm {configure|createdisk|deletedisk|querydisk|listdisks|scandisks|status}

Ok… So, what to do?

Take a look:

[root@dbsrv01 ~]# oracleasm init
Creating /dev/oracleasm mount point: /dev/oracleasm
Loading module "oracleasm": oracleasm
Configuring "oracleasm" to use device physical block size
Mounting ASMlib driver filesystem: /dev/oracleasm

Victory!
Now, let’s configure:

[root@dbsrv01 ~]# oracleasm configure
ORACLEASM_UID=
ORACLEASM_GID=
ORACLEASM_SCANBOOT=true
ORACLEASM_SCANORDER=""
ORACLEASM_SCANEXCLUDE=""
ORACLEASM_USE_LOGICAL_BLOCK_SIZE="false"

It shows, but how configure?

Just put “-i” clause, like:

[root@dbsrv01 ~]# oracleasm configure -i
Configuring the Oracle ASM library driver.
This will configure the on-boot properties of the Oracle ASM library
driver.  The following questions will determine whether the driver is
loaded on boot and what permissions it will have.  The current values
will be shown in brackets ('[]').  Hitting  without typing an
answer will keep that current value.  Ctrl-C will abort.
Default user to own the driver interface []: grid
Default group to own the driver interface []: oinstall
Scan for Oracle ASM disks on boot (y/n) [y]: y
Writing Oracle ASM library driver configuration: done

And you can list again:

[root@dbsrv01 ~]# oracleasm configure
ORACLEASM_UID=grid
ORACLEASM_GID=oinstall
ORACLEASM_SCANBOOT=true
ORACLEASM_SCANORDER=""
ORACLEASM_SCANEXCLUDE=""
ORACLEASM_USE_LOGICAL_BLOCK_SIZE="false"
[root@dbsrv01 ~]# oracleasm status
Checking if ASM is loaded: yes
Checking if /dev/oracleasm is mounted: yes

To add a disk, the same process can be followed on earlier versions:

[root@dbsrv01 ~]# oracleasm createdisk SDD /dev/sdd1
Writing disk header: done
Instantiating disk: done
[root@dbsrv01 ~]# oracleasm listdisks
SDD

For all commands:

[root@dbsrv01 ~]# oracleasm -h
Usage: oracleasm [--exec-path=]  [  ]
oracleasm --exec-path
oracleasm -h
oracleasm -V
The basic oracleasm commands are:
configure        Configure the Oracle Linux ASMLib driver
init             Load and initialize the ASMLib driver
exit             Stop the ASMLib driver
scandisks        Scan the system for Oracle ASMLib disks
status           Display the status of the Oracle ASMLib driver
listdisks        List known Oracle ASMLib disks
querydisk        Determine if a disk belongs to Oracle ASMlib
createdisk       Allocate a device for Oracle ASMLib use
deletedisk       Return a device to the operating system
renamedisk       Change the label of an Oracle ASMlib disk
update-driver    Download the latest ASMLib driver

And to see arguments for each one:

[root@dbsrv01 ~]# oracleasm configure -h
Usage: oracleasm-configure [-l ] [-i|-I] [-e|-d] [-u ] [-g ] [-b|-p] [-s y|n] [[-o ] ...] [[-x ] ...]

Have a nice day!
See ya!
Matheus.

Adding datafile hang on “enq: TT – contention”

Yesterday a colegue asked me about “enq: TT – contention” event on his session that is adding a a datafile in a tablespace wich run out of space in a 11.1.0.7 Database.
I’ve faced this situation another time and decided to document it.

Oracle refer Bug 8332021 : CANNOT ADD A DF WHEN SESSIONS ARE REPORTING ORA-1653 ON 11.1.0.7 for this situation.

The pointing solutions are:
– “Apply Patch 8332021”
– “Alternatively, you can upgrade to 11.2.0.2 or higher as the patch is included in the 11.2.0.2 patch set.”

The not documented workaround (just for you, by Matheus :D) is:
– Cancel session adding datafile.
– Extend any datafile to resume sessions waiting (in resumable state).
– Readd datafile.
This extend action relieves the blocks and will allow you to add the datafile.

Hugs!

Matheus.

ORA-15081: failed to submit an I/O operation to a disk

After some disk and a instance of RAC lost, the database was stuck with ORA-15081.
A recover was needed. #StayTheTip

# Error

dbsrvr:/home/oracle>sqlplus / as sysdba
SQL*Plus: Release 11.2.0.2.0 Production on Fri Jun 29 19:51:37 2015
Copyright (c) 1982, 2010, Oracle. All rights reserved.
Connected to an idle instance.
SQL> startup mount;
ORACLE instance started.
Total System Global Area 1.3462E+10 bytes
Fixed Size 2239232 bytes
Variable Size 7214204160 bytes
Database Buffers 6241124352 bytes
Redo Buffers 4489216 bytes
Database mounted.
SQL> alter database open;
alter database open
*
ERROR at line 1:
ORA-15081: failed to submit an I/O operation to a disk

# Solution

SQL> recover database;
Media recovery complete.
SQL> alter database open;
Database altered.

Be happy with this! 😀

Matheus.

Adding ASM Disks on RHEL Cluster with Failgroups

# Recognizing as ASMDISK on ASM Libs (ORACLEASM):

1) All cluster nodes: /etc/init.d/oracleasm scandisk
[root@db1host1p ~]# /etc/init.d/oracleasm scandisks
Scanning the system for Oracle ASMLib disks: [ OK ]
[root@db2host2p ~]# /etc/init.d/oracleasm scandisks
Scanning the system for Oracle ASMLib disks: [ OK ]

2) One of cluster nodes:
[root@db1host1p ~]# /etc/init.d/oracleasm createdisk DGDATA059 /dev/asmdsk/DGDATA059
Marking disk "DGDATA059" as an ASM disk: [ OK ]
[root@db1host1p ~]# /etc/init.d/oracleasm createdisk DGDATA060 /dev/asmdsk/DGDATA060
Marking disk "DGDATA060" as an ASM disk: [ OK ]
[root@db1host1p ~]# /etc/init.d/oracleasm createdisk DGDATA061 /dev/asmdsk/DGDATA061
Marking disk "DGDATA061" as an ASM disk: [ OK ]
[root@db1host1p ~]# /etc/init.d/oracleasm createdisk DGDATA062 /dev/asmdsk/DGDATA062
Marking disk "DGDATA062" as an ASM disk: [ OK ]
[root@db1host1p ~]# /etc/init.d/oracleasm createdisk DGDATA159 /dev/asmdsk/DGDATA159
Marking disk "DGDATA159" as an ASM disk: [ OK ]
[root@db1host1p ~]# /etc/init.d/oracleasm createdisk DGDATA160 /dev/asmdsk/DGDATA160
Marking disk "DGDATA160" as an ASM disk: [ OK ]
[root@db1host1p ~]# /etc/init.d/oracleasm createdisk DGDATA161 /dev/asmdsk/DGDATA161
Marking disk "DGDATA161" as an ASM disk: [ OK ]
[root@db1host1p ~]# /etc/init.d/oracleasm createdisk DGDATA162 /dev/asmdsk/DGDATA162
Marking disk "DGDATA162" as an ASM disk: [ OK ]

3) All cluster nodes: /etc/init.d/oracleasm scandisk
[root@db1host1p ~]# /etc/init.d/oracleasm scandisks
Scanning the system for Oracle ASMLib disks: [ OK ]
[root@db2host2p ~]# /etc/init.d/oracleasm scandisks
Scanning the system for Oracle ASMLib disks: [ OK ]

# Adding Disk on Diskgroup (sqlplus / as sysasm – ASM Instance)
1) Listing Failgroups
SQL> select distinct failgroup from v$asm_disk where group_number in (select group_number from v$asm_diskgroup where name='DGDATA');
FAILGROUP
----------------------------------------------------
FGMASTER
FGAUX

1) Adding Disks (naming and setting rebalance power):
SQL> alter diskgroup DGDATA
2 add failgroup FG01 disk
3 'ORCL:DGDATA059' name DGDATA059,
4 'ORCL:DGDATA060' name DGDATA060,
5 'ORCL:DGDATA061' name DGDATA061,
6 'ORCL:DGDATA062' name DGDATA062
7 add failgroup FG02 disk
8 'ORCL:DGDATA159' name DGDATA159,
9 'ORCL:DGDATA160' name DGDATA160,
10 'ORCL:DGDATA161' name DGDATA161,
11 'ORCL:DGDATA162' name DGDATA162
12 rebalance power 10 nowait;
Diskgroup altered

2) Be patient, and wait the rebalancing:
SQL> select * from v$asm_operation;
GROUP_NUMBER OPERATION STATE POWER ACTUAL SOFAR EST_WORK EST_RATE EST_MINUTES ERROR_CODE
------------ ----------- ---------- ---------- ---------- -----------
4 REBAL RUN 10 10 191386 540431 1651 211 5 REBAL WAIT 4
SQL> /
GROUP_NUMBER OPERATION STATE POWER ACTUAL SOFAR EST_WORK EST_RATE EST_MINUTES ERROR_CODE
------------ --------------- ----------------------------------------
4 REBAL RUN 10 10 443438 548118 2345 44 5 REBAL WAIT 4
SQL> /
no rows selected

Well done! 😀
Matheus.

ASM: Adding disk “_DROPPED%” FORCE

Ok doke,
First let I make it clear: Adding a disk with force should be avoided, mainly by all the rebalance involved. The best choice, if you has “time”, is to just put disks online, like:

1) ALTER DISKGROUP ONLINE DISK ; or
2) ALTER DISKGROUP ONLINE DISKS IN FAILGROUP ; or
3) ALTER DISKGROUP ONLINE ALL;

But, the post is about adding back to DG the dropped disks.
Let’s imagine, to undestand my situation, you lost the contact with one of your two site storage… In this example, represented by failgroup FGAUX. You would see the disks like this:

SQL> select name,failgroup,state from v$asm_disk a where state <> 'NORMAL';

NAME FAILGROUP STATE
------------------------------ ------------------------------ --------
_DROPPED_0000_DGDATA FGAUX FORCING
_DROPPED_0001_DGDATA FGAUX FORCING
_DROPPED_0002_DGDATA FGAUX FORCING

So, you know your disks by the name pattern (0 are FGMAIN and 1 are FGAUX, the problematic). You can do something like:

[root@database-host ~]# /etc/init.d/oracleasm listdisks |grep DGDATA
DGDATA001
DGDATA002
DGDATA003
DGDATA101
DGDATA102
DGDATA103

Now, make the simple… 🙂

SQL> ALTER DISKGROUP DGDATA ADD
FAILGROUP FGAUX
DISK
'ORCL:DGDATA101' name DGDATA101 FORCE,
'ORCL:DGDATA102' name DGDATA102 FORCE,
'ORCL:DGDATA103' name DGDATA103 FORCE;

Diskgroup altered.

SQL> ALTER DISKGROUP DGDATA rebalance power 8;

Diskgroup altered.

While waiting the reball, let’s see the disks in DG:

SQL> select * from v$asm_operation where group_number=(select group_number from v$asm_diskgroup where name='DGDATA');

GROUP_NUMBER OPERA STAT POWER ACTUAL SOFAR EST_WORK EST_RATE EST_MINUTES ERROR_CODE
------------ ----- ---- ---------- ---------- ---------- ---------- ---------- ----------- --------------------------------------------
3 REBAL WAIT 8
SQL> select name,failgroup,state from v$asm_disk a where group_number=(select group_number from v$asm_diskgroup where name='DGDATA');

NAME FAILGROUP STATE
------------------------------ ------------------------------ --------
_DROPPED_0000_DGDATA FGAUX FORCING
_DROPPED_0001_DGDATA FGAUX FORCING
_DROPPED_0002_DGDATA FGAUX FORCING
DGDATA101 FGAUX NORMAL
DGDATA102 FGAUX NORMAL
DGDATA103 FGAUX NORMAL
DGDATA001 FGMAIN NORMAL
DGDATA002 FGMAIN NORMAL
DGDATA003 FGMAIN NORMAL

And, when the rebalance end, the situation will be OK:

SQL> select * from v$asm_operation where group_number=(select group_number from v$asm_diskgroup where name='DGDATA');

GROUP_NUMBER OPERA STAT POWER ACTUAL SOFAR EST_WORK EST_RATE EST_MINUTES ERROR_CODE
------------ ----- ---- ---------- ---------- ---------- ---------- ---------- ----------- --------------------------------------------
3 REBAL RUN 8 8 629 19087 10143 1

SQL> select * from v$asm_operation where group_number=(select group_number from v$asm_diskgroup where name='DGDATA');

no rows selected

SQL> select name,failgroup,state from v$asm_disk a where group_number=(select group_number from v$asm_diskgroup where name='DGDATA');

NAME FAILGROUP STATE
------------------------------ ------------------------------ --------
DGDATA101 FGAUX NORMAL
DGDATA102 FGAUX NORMAL
DGDATA103 FGAUX NORMAL
DGDATA001 FGMAIN NORMAL
DGDATA002 FGMAIN NORMAL
DGDATA003 FGMAIN NORMAL

OK? Easy! 😀

Matheus.

GB vs GiB | MB vs MiB | KB vs KiB

Oh man!
It’s just me or you doesn’t know about too?

Okey. Here the difference is well explained. I saw it for the first time in EMC DataDomain interface and it sounded a little “strange”, but ok. Last week a heard a friend talking about and decided to search… What a surprise! haha

gibibyte-vs-gigabyte-small

In a nutshell, the units as we know them (1Gigabyte = 1000 Megabytes) was proposed by  Système International D’Unités (SI) and the other way (1Gibibyte = 1024 Mebibytes, with much more “precision”) was proposed by International Electrotechnical Commission’s (IEC), in 1999.
The main difference is that the first uses 10^x measurement, rather than 2^x (1024 base), like IEC. For example:

For a DVD:
4.7 GB ==> 4.337 GiB
8.5 GB ==> 7.91 GiB

Interesting, isn’t it?
So, again, I suggest you spend some time reading this

Matheus.