Oracle RAC Flash Area Usage Test

The Flash Recovery Area is a specific area of disk storage that is set aside exclusively for retention of backup components such as datafile image copies, archived redo logs, and control file autobackup copies. These features include:

  • Unified Backup Files Storage. All backup components can be stored in one consolidated spot. The Flash Recovery Area is managed via Oracle Managed Files (OMF), and it can utilize disk resources managed by Oracle Automated Storage Management (ASM). In addition, the Flash Recovery Area can be configured for use by multiple database instances if so desired.
  • Automated Disk-Based Backup and Recovery. Once the Flash Recovery Area is configured, all backup components (datafile image copies, archived redo logs, and so on) are managed automatically by Oracle.
  • Automatic Deletion of Backup Components. Once backup components have been successfully created, RMAN can be configured to automatically clean up files that are no longer needed (thus reducing risk of insufficient disk space for backups).
  • Disk Cache for Tape Copies. Finally, if your disaster recovery plan involves backing up to alternate media, the Flash Recovery Area can act as a disk cache area for those backup components that are eventually copied to tape.
  • Flashback Logs. The Flash Recovery Area is also used to store and manage flashback logs, which are used during Flashback Backup operations to quickly restore a database to a prior desired state.

Oracle recommends that the Flash Recovery Area should be sized large enough to include all files required for backup and recovery. Using this test, administrators can figure out whether the Flash Recovery Area is adequately sized or not, and accordingly make sizing recommendations.

Note:

  • This test is applicable only to clusters based on Oracle database server 10g (and above).

  • This test is applicable only for CDB(Container Database) configuration of Oracle Clusters with Multi-tenant support.

Target of the test : An Oracle database server 10g

Agent deploying the test : An internal agent

Outputs of the test : One set of results for the flash recovery area on each node in the Oracle cluster

Configurable parameters for the test
Parameters Description

Test period

How often should the test be executed. By default, this is set to 60 minutes.

Host

The IP address of the Oracle server.

Port

The port number through which the Oracle server communicates. The default port is 1521.

SCAN Name

SCAN stands for Single Client Access Name, it is a feature used in Oracle RAC environments that provide a single name for clients to access any Oracle Database running in the cluster. You can provide SCAN as an alternative to IP/Host Name. If this parameter value is provided, it will be used for connectivity otherwise IP/Hostname will be used.

OraSID

The variable name of the oracle instance.

ServiceName

A ServiceName exists for the entire Oracle RAC system. When clients connect to an Oracle cluster using the ServiceName, then the cluster routes the request to any available database instance in the cluster. By default, this is set to none. In this case, the test connects to the cluster using the OraaSID and pulls out the metrics from that database instance which corresponds to that OraSID. If a valid service nameis specified instead, then, the test will connect to the cluster using that service name, and will be able to pull out metrics from any available database instance in the cluster.

To know the ServiceName of a cluster, execute the following query on any node in the target cluster:

select name, value from v$parameter where name =’service_names’

User

In order to monitor an Oracle RAC, a special database user account has to be User – In order to monitor an Oracle database server, a special database user account has to be created in every Oracle database instance that requires monitoring. A Click here hyperlink is available in the test configuration page, using which a new oracle database user can be created. Alternatively, you can manually create the special database user. When doing so, ensure that this user is vested with the select_catalog_role and create session privileges.

The sample script we recommend for user creation (in Oracle database server versions before 12c) for eG monitoring is:

create user oraeg identified by oraeg create role oratest;

grant create session to oratest;

grant select_catalog_role to oratest;

grant oratest to oraeg;

The sample script we recommend for user creation (in Oracle database server 12c) for eG monitoring is:

alter session set container=<Oracle_service_name>;

create user <user_name>identified by <user_password> container=current default tablespace <name_of_default_tablespace> temporary tablespace <name_of_temporary_tablespace>;

Grant create session to <user_name>;                                 

Grant select_catalog_role to <user_name>;

The name of this user has to be specified here.

Password

Specify the password corresponding to the mentioned user.

Confirm Password

Confirm the password by retyping it.

SSL

By default, this flag is set to No, as the target Oracle cluster is not SSL-enabled by default. If the target cluster is SSL-enabled, then set this flag to Yes.

SSL Cipher

This parameter is applicable only if the target Oracle Cluster is SSL-enabled, if not, set this parameter to none. A cipher suite is a set of cryptographic algorithms that are used before a client application and server exchange information over an SSL/TLS connection. It consist of sets of instructions on how to secure a network through SSL (Secure Sockets Layer) or TLS (Transport Layer Security). In this text box, provide a comma-seperated list of cipher suites that are allowed for SSL/TLS connection to the target cluster. By default, this parameter is set to none.

Truststore File

This parameter is applicable only if the target Oracle Cluster is SSL-enabled, if not, set this parameter to none. TrustStore is used to store certificates from Certified Authorities (CA) that verify and authenticate the certificate presented by the server in an SSL connection. Therefore, the eG agent should have access to the truststore where the certificates are stored to authenticate and connect with the target cluster and collect metrics. For this, first import the certificates into the following default location <eG_INSTALL_DIR>/lib/security/mytruststore.jks. To know how to import the certificate into the truststore, refer toPre-requisites for monitoring Oracle Cluster. Then, provide the truststore file name in this text box. For example: mytruststore.jks. By default, none is specified against this text box.

Truststore Type

This parameter is applicable only if the target Oracle Cluster is SSL-enabled, if not, set this parameter to none.Specify the type of truststore that contains the certificates for server authentication in this text box. For eg.,JKS. By default, this parameter is set to the value none.

Truststore Password

This parameter is applicable only if the target Oracle Cluster is SSL-enabled, if not, set this parameter to none. If a Truststore File name is provided, then, in this text box, provide the password that is used to obtain the associated certificate details from the Truststore File. By default, this parameter is set to none.

Keystore File

This parameter is applicable only if the target Oracle Cluster is SSL-enabled, if not, set this parameter to none.

Keystore contains the private keys for the certificates that the client can provide to the server upon request. eG agent requires access to the keystore where client certificate is stored to send that to the server so that the server validates the certificate against the one contained in its trustore. For this purpose, first create the client certificate in the following default location EG_INSTALL_DIR/jre/lib/security/mykeystore.jks. Then, provide the keystore file name in this text box. For example: mykeystore.jks. By default, none is specified against this text box.

Keystore Password

This parameter is applicable only if the target Oracle Cluster is SSL-enabled, if not, set this parameter to none.

If a Keystore File name or file path is provided, then, in this text box, provide the password that is used to obtain the associated certificate details from the Keystore File.

Confirm Password

Confirm the Password for Keystore by retyping it here.

Measurements made by the test
Measurement Description Measurement Unit Interpretation

Used flash area:

Indicates the space currently occupied by the flash recovery files on this node.

 

MB

 

Maximum flash area size:

Indicates the maximum space allocated for flash recovery files on this node.

MB

 

 

Flash area usage: 

Indicates the percentage of space occupied by the flash recovery files on this node.

Percent

Oracle recommends that the Flash Recovery Area should be sized large enough to include all files required for backup and recovery. Therefore, ideally, the value of this measure should be very low. A value close to 100% indicates excessive usage of the recovery area; this implies that the flash recovery area could soon run out of space.  in such a case you can resize the flash recovery area by reconfiguring the parameter “db_recovery_file_dest_size” in database parameter file, provided enough disk space is available. If not, then Oracle recommends that the flash area be sized at least large enough to contain any archived redo logs that have not yet been backed up to alternate media.

Alternatively, you can remove the old files from the flash recovery area to create space for the new recovery files.

Free flash area:

Indicates the free space currently available for recovery files on this node.

Percentage