Tag: real application Cluster

Some Basic To backup Voting Disk And OCR For Oracle RAC

Posted on by Osama Mustafa in Database
We Need To Backup Voting Disk and OCR For Oracle RAC For Disaster Situation :

Add Voting Disk :

# crsctl add css votedisk

To remove a voting disk:

# crsctl delete css votedisk

If Oracle Clusterware is down on all nodes, use the –force option:

# crsctl add css votedisk -force
# crsctl delete css votedisk -force

 Backup Voting Disk :

$ crsctl query css votedisk
$ dd if= of= bs=4k

OCR BACKUP :

Oracle RAC Taking Backup For OCR By Default , You will Find It On :

 cd $ORACLE_BASE/Crs/cdata/jfv_clus

Change the default automatic backup location:

# ocrconfig –backuploc /shared/bak

Back Up OCR Manually :

 # ocrconfig –export file name

 Recover OCR Using Physical Backups:

1.Locate a physical backup:
 $ ocrconfig –showbackup
2.Review its contents:

# ocrdump –backupfile file_name
 3.Stop Oracle Clusterwareon all nodes:

 # crsctl stop crs
4.Restore the physical OCR backup:

# ocrconfig –restore <CRS HOME>/cdata/jfv_clus/day.ocr

5.Restart Oracle Clusterware on all nodes:

 # crsctl start crs
6.Check OCR integrity:

$ cluvfy comp ocr -n all

Thank You
Osama Mustafa 

 



UNKNOWN State Of RAC Resources

Posted on by Osama Mustafa in Database
Sometimes when you check Oracle Cluster Status Via “crs_stat -t” :

------------------------------------------------------------
ora.orcl.db    application    ONLINE    ONLINE    rac1
ora....11.inst application    ONLINE    ONLINE    rac1
ora....SM1.asm application    ONLINE    ONLINE    rac1
ora....DC.lsnr application    ONLINE    ONLINE    rac1
ora....idc.gsd application    ONLINE    ONLINE    rac1
ora....idc.ons application    ONLINE    ONLINE    rac1
ora....idc.vip application    ONLINE    ONLINE    rac1
ora....SM2.asm application    ONLINE    UNKNOWN   rac2
ora....C2.lsnr application    ONLINE    ONLINE    rac2
ora....dc2.gsd application    ONLINE    ONLINE    rac2
ora....dc2.ons application    ONLINE    ONLINE    rac2
ora....dc2.vip application    ONLINE    ONLINE    rac2

If You try to restart Oracle Cluster via

./crs_stop -all
./crs_start -all

It will not working so you have to do the following simple steps :

 First :

crs_stop -f Service_name
 
Example :
crs_stop -f ora.rac2.ASM2.asm

 Second :

crs_start -f services_name

Example :

crs_start -f ora.rac2.ASM2.asm

Thank you
Osama

Checking O2CB heartbeat: Not active

Posted on by Osama Mustafa in Database

[root@rac01]# /etc/init.d/o2cb  status

Module “configfs”: Loaded
Filesystem “configfs”: Mounted
Module “ocfs2_nodemanager”: Loaded
Module “ocfs2_dlm”: Loaded
Module “ocfs2_dlmfs”: Loaded
Filesystem “ocfs2_dlmfs”: Mounted
Checking O2CB cluster ocfs2: Online
  Heartbeat dead threshold: 61
  Network idle timeout: 30000
  Network keepalive delay: 2000
  Network reconnect delay: 2000
Checking O2CB heartbeat: Not active

The Solution like the Following :

[root@rac01]# /etc/init.d/o2cb  configure

Configuring the O2CB driver.
This will configure the on-boot properties of the O2CB driver.
The following questions will determine whether the driver is loaded on
boot.  The current values will be shown in brackets (‘[]’).  Hitting
without typing an answer will keep that current value.  Ctrl-C
will abort.
Load O2CB driver on boot (y/n) [y]: y
Cluster to start on boot (Enter “none” to clear) [ocfs2]:
Specify heartbeat dead threshold (>=7) [31]: 61
Specify network idle timeout in ms (>=5000) [30000]:
Specify network keepalive delay in ms (>=1000) [2000]:
Specify network reconnect delay in ms (>=2000) [2000]:
Writing O2CB configuration: OK
O2CB cluster ocfs2 already online

[root@rac01]# /etc/init.d/o2cb  stop
Stopping O2CB cluster ocfs2: OK
Unmounting ocfs2_dlmfs filesystem: OK
Unloading module “ocfs2_dlmfs”: OK
Unmounting configfs filesystem: OK
Unloading module “configfs”: OK

 [root@rac01]# /etc/init.d/o2cb  start
Loading module “configfs”: OK
Mounting configfs filesystem at /config: OK
Loading module “ocfs2_nodemanager”: OK
Loading module “ocfs2_dlm”: OK
Loading module “ocfs2_dlmfs”: OK
Mounting ocfs2_dlmfs filesystem at /dlm: OK
Starting O2CB cluster ocfs2: OK

Now

  [root@rac01]# ocfs2console

Then Mount Command .

Instance Recovery and RAC

Posted on by Osama Mustafa in Database

Here are some guidelines you can use to make sure that instance recovery in your RAC environment is faster:
•Use parallel instance recovery by setting RECOVERY_PARALLISM.
•Increase PARALLEL_EXECUTION_MESSAGE_SIZE from its default of 2,148 bytes to 4 KB or 8 KB. This should provide better recovery slave performance.
•Set PARALLEL_MIN_SERVERS to CPU_COUNT-1. This will prespawnrecovery slaves at startup time.
•Using asynchronous I/O is one of the most crucial factors in recovery time. The first-pass log read uses asynchronous I/O.
•Instance recovery uses 50 percent of the default buffer cache for recovery buffers. If this is not enough, some of the steps of instance recovery will be done in several passes. You should be able to identify such situations by looking at your alert.logfile. In that case, you should increase the size of your default buffer cache.

ocfs2console: o2cb_ctl: Unable to access cluster service while creating node

Posted on by Osama Mustafa in Database
For the first time, during configuring the nodes, ocfs2console fails with message:
“o2cb_ctl: Unable to access cluster service while creating node”
TODO:
– Quit ocfs2console
– Stop the service
– Remove file /etc/ocfs2/cluster.conf
– Restart ocfs2console
– Configure the nodes again

[root@rac1 ~]#  /etc/init.d/ocfs2 stop
Stopping Oracle Cluster File System (OCFS2)                [  OK  ]

[root@rac1 ~]# /etc/init.d/o2cb offline ocfs2

[root@rac1 ~]# /etc/init.d/o2cb unload
Unmounting ocfs2_dlmfs filesystem: OK
Unloading module "ocfs2_dlmfs": OK
Unmounting configfs filesystem: OK
Unloading module "configfs": OK

[root@rac1 ~]# rm -f /etc/ocfs2/cluster.conf
[root@rac1 ~]# /usr/sbin/ocfs2console &

Oracle Real Application Cluster Lesson # 1

Posted on by Osama Mustafa in Database
Sometimes we need Solutions to keep our database Available all the time, There are lot of solutions one of these solutions called  Oracle Real Application Cluster (RAC)/High Availability

As Lesson Number One i will take on Oracle Real Application Cluster Basics .

Lets Start :

Oracle RAC allows multiple computers to run Oracle RDBMS software simultaneously while accessing a single database, thus providing a clustered database.
In a non-RAC Oracle database, a single instance accesses a single database. The database consists of a collection of data files, control files, and redo logs located on disk. The instance comprises the collection of Oracle-related memory and operating system processes that run on a computer system.
In an Oracle RAC environment, two or more computers (each with an instance) concurrently access a single database. This allows an application or user to connect to either computer and have access to a single coordinated set of data.
Assume the  installation of Oracle 10g release 2 (10.2) RAC on Red Hat Enterprise Linux 4.

Hardware
At the hardware level, each node in a RAC cluster shares three things:

  1. Access to shared disk storage
  2. Connection to a private network
  3. Access to a public network.

 

Shared Disk Storage
Oracle RAC relies on a shared disk architecture. The database files, online redo logs, and control files for the database must be accessible to each node in the cluster. The shared disks also store the Oracle Cluster Registry and Voting Disk (discussed later). There are a variety of ways to configure shared storage including direct attached disks (typically SCSI over copper or fiber), Storage Area Networks (SAN), and Network Attached Storage (NAS).

Supported Shared Storage In RAC :

1-Oracle Cluster File System (OCFS) is a shared file system designed specifically for Oracle Real Application Cluster OCFS eliminates the requirement that Oracle database files be linked to logical drives and enables all nodes to share a single Oracle Home
2-ASM
3-RAW Device

Private Network
Each cluster node is connected to all other nodes via a private high-speed network, also known as the cluster interconnect or high-speed interconnect (HSI). This network is used by Oracle’s Cache Fusion technology to effectively combine the physical memory (RAM) in each host into a single cache. Oracle Cache Fusion allows data stored in the cache of one Oracle instance to be accessed by any other instance by transferring it across the private network. It also preserves data integrity and cache coherency by transmitting locking and other synchronization information across cluster nodes.
The private network is typically built with Gigabit Ethernet, but for high-volume environments, many vendors offer proprietary low-latency, high-bandwidth solutions specifically designed for Oracle RAC. Linux also offers a means of bonding multiple physical NICs into a single virtual NIC (not covered here) to provide increased bandwidth and availability.

Public Network
To maintain high availability, each cluster node is assigned a virtual IP address (VIP). In the event of node failure, the failed node’s IP address can be reassigned to a surviving node to allow applications to continue accessing the database through the same IP address.

Configuring the Cluster Hardware
There are many different ways to configure the hardware for an Oracle RAC cluster. Our configuration here uses two servers with two CPUs, 1GB RAM, two Gigabit Ethernet NICs, a dual channel SCSI host bus adapter (HBA), and eight SCSI disks connected via copper to each host (four disks per channel). The disks were configured as Just a Bunch Of Disks (JBOD)—that is, with no hardware RAID controller. 


Software
At the software level, each node in a RAC cluster needs:

  1. An operating system
  2. Oracle Clusterware
  3. Oracle RAC software
  4. An Oracle Automatic Storage Management (ASM) instance (optional).

Operating System
Oracle RAC is supported on many different operating systems. This guide focuses on Linux. The operating system must be properly configured for the OS–including installing the necessary software packages, setting kernel parameters, configuring the network, establishing an account with the proper security, configuring disk devices, and creating directory structures. All these tasks are described in this guide.

Oracle Cluster Ready Services becomes Oracle Clusterware
Oracle RAC 10g Release 1 introduced Oracle Cluster Ready Services (CRS), a platform-independent set of system services for cluster environments. In Release 2, Oracle has renamed this product to Oracle Clusterware.
Clusterware maintains two files: the Oracle Cluster Registry (OCR) and the Voting Disk. The OCR and the Voting Disk must reside on shared disks as either raw partitions or files in a cluster filesystem. This guide describes creating the OCR and Voting Disks using a cluster filesystem (OCFS2) and walks through the CRS installation.

Oracle RAC Software
Oracle RAC 10g Release 2 software is the heart of the RAC database and must be installed on each cluster node. Fortunately, the Oracle Universal Installer (OUI) does most of the work of installing the RAC software on each node. You only have to install RAC on one node—OUI does the rest.

Oracle Automatic Storage Management (ASM) / Or other shared Storage .
ASM is a new feature in Oracle Database 10g that provides the services of a filesystem, logical volume manager, and software RAID in a platform-independent manner. Oracle ASM can stripe and mirror your disks, allow disks to be added or removed while the database is under load, and automatically balance I/O to remove “hot spots.” It also supports direct and asynchronous I/O and implements the Oracle Data Manager API (simplified I/O system call interface) introduced in Oracle9i.

Some Other Stuff you need To check Before Installation : 

1-Crossover cables are not supported (use a high-speed switch).
2-Use at least a gigabit Ethernet for optimal performance.
3-Increase the UDP buffer sizes to the OS maximum.
4-Turn on UDP checksumming.
5-Oracle Support strongly recommends the use of UDP (TCP for WIndows )
6-SSH Connectivity .

Thank you
Osama mustafa

Resize Redolog On RAC Instance

Posted on by Osama Mustafa in Database
Before I Posted “How To Resize redo log ” This was on Single Instance But Now I show you how to do it on Oracle Real Application Cluster



1.First Run this Query To check size, redo On your RAC :

select l.group#, l.thread#, f.member, l.archived, l.status, (bytes/1024/1024) fsize
from v$log l, v$logfile f
where f.group# = l.group#
order by 1,2


2. Now our purpose is increase redosize from 100Mb to 300 Mb

3. We are going to add our new redo file by below command:

4.
alter database add logfile group 5 ‘+ORADATA’ size 300M;    <<   node 2
alter database add logfile group 6 ‘+ORADATA’ size 300M;    <<   node 2
alter database add logfile group 7 ‘+ORADATA’ size 300M;    <<   node 1
alter database add logfile group 8 ‘+ORADATA’ size 300M;    <<   node 1

5. Switch until we are into log group 5,6,7,8 so we can drop log groups 1, 2,3 and 4 Until you see the new redo log used .

Thank you
Osama mustafa