Interview Questions.

Q1. We Are Migrating To A New Storage Array. How Do I Move My Asm Database From Storage A To Storage B?

Given that the new and antique garage are each seen to ASM, really add the brand new disks to the ASM disk institution and drop the antique disks. ASM rebalance will migrate information online.

 

Q2. What Is Grd?

GRD stands for Global Resource Directory. The GES and GCS hold data of the reputation of each datafile and each cached block the use of global aid directory. This procedure is called cache fusion and facilitates in records integrity.

Q3. How Do I Backup My Asm Instance?

Not relevant! ASM has no documents to backup, as its does no longer incorporate controlfile,redo logs and many others.

Q4. When Should I Use Rman And When Should I Use Asmcmd Copy?

RMAN is the recommended and maximum entire and flexible technique to backup and trport database documents in ASM.

ASMCMD copy is right for copying unmarried documents

• Supports all Oracle document kinds

• Can be used to instantiate a Data Guard environment

• Does not replace the controlfile

• Does no longer create OMF documents

Q5. What Is A Crs Resource?

Oracle Clusterware is used to manipulate high-availability operations in a cluster. Anything that Oracle Clusterware manages is known as a CRS aid. Some examples of CRS resources are database, an instance, a carrier, a listener, a VIP deal with, an utility process and many others.

Q6. What Is The Function Of Cache Fusion In Oracle Rac?

Cache characteristic is used to show the garage of the facts within the clustered network with the Oracle database.

This uses the database trfer medium and it includes two nodes in which one reads the records block from the disk and any other write the records to the identical disk.

It provides very good performance and increases the flexibility in phrases of execution of the software that is using the platform.

RAC uses a committed server for its community connection and the cache fusion is an inner component to the cluster.

It uses the equal database and maintains the things in the cache till the information isn't always needed anymore by using another utility. It queries the information best while it definitely necessary to do it.

The question from the consumer continually results within the maximum contemporary version even after the data is being changed.

Q7. What Are The Key Benefits Of Asm?

ASM gives filesystem and volume manager skills built into the Oracle database kernel. Withthis capability, ASM simplifies garage control obligations, including growing/laying out databases and disk area control. Since ASM allows disk control to be completed the use of familiar create/adjust/drop SQL statements, DBAs do not want to analyze a new skill set or make essential selections on provisioning.

The following are a few key advantages of ASM:

ASM spreads I/O calmly across all available disk drives to prevent hot spots and maximize performance.

ASM removes the want for over provisioning and maximizes garage resource usage facilitating database consolidation.

Inherent huge file help.

Performs automatic on-line redistribution after the incremental addition or elimination of storage  capability.

Maintains redundant copies of data to provide excessive availability, or leverages third birthday party RAID capability.

Supports Oracle Database as well as Oracle Real Application Clusters (RAC).

Capable of leveraging 3rd celebration multipathing technology.

For simplicity and less complicated migration to ASM, an Oracle database can include ASM and non-ASM documents.

Any new files may be created as ASM files at the same time as existing documents also can be migrated to ASM.

RMAN instructions permit non-ASM managed files to be relocated to an ASM disk group.

Enterprise Manager Database Control or Grid Control may be used to control ASM disk and document sports.
 

Q8. Where Are The Clusterware Files Stored On A Rac Environment?

The Clusterware is set up on every node (on an Oracle Home) and on the shared disks (the voting disks and the CSR file).

Q9. What Are The Types Of Connection Load-balancing?

There are  types of connection load-balancing: server-aspect load balancing and consumer-side load balancing.

Q10. What Is A Diskgroup?

A disk organization includes multiple disks and is the essential object that ASM manages. Each disk institution contains the metadata that is required for the management of space inside the disk organization. The ASM example manages the metadata about the files in a Disk Group in the identical way that a file machine manages metadata about its files. However, the significant majority of I/O operations do now not skip through the ASM instance. In a moment we can examine how report I/O works with recognize to the ASM example.

Q11. How Does An Oracle Clusterware Manage Crs Resources?

Oracle Clusterware manages CRS sources primarily based on the configuration statistics of CRS resources stored in OCR (Oracle Cluster Registry).

Q12. What Is Asm Striping?

ASM can use variable size facts extents to aid larger files, lessen reminiscence requirements, and improve overall performance.

Each facts quantity is living on an person disk.

Data extents consist of one or more allocation gadgets.

The facts quantity size is:

Equal to AU for the first 20,000 extents (0–19999)

Equal to four × AU for the subsequent 20,000 extents (20000–39999)

Equal to 16 × AU for extents above 40,000

ASM stripes documents using extents with a coarse approach for load balancing or a best method to reduce latency.

Coarse-grained striping is continually equal to the powerful AU length.

Fine-grained striping is constantly equal to 128 KB.

Q13. What Is Required By Oracle Rac Database To Connect To A Network?

Oracle RAC calls for an lively connection of the network to the LAN (Local Area Network) so that the database server can be located and related.

The database server is in addition having connections with application servers that save the applications and permit person to trfer their data.

The connection is required with the server pool so that the trfer of services and packages may be completed on call for foundation.

The interconnection between the networks is truely vital as it has to preserve the overall go with the flow of the swimming pools and the assets.

Oracle RAC provides support to redundant interconnects particularly and it offers an typical infrastructure answer.

The load balancing and inter-node messaging can be treated extra carefully while the networks or the servers are interconnected to every other.

Q14. Do I Need To Define The Rdbms Filesystemio_options Parameter When I Use Asm?

No. The RDBMS does I/O at once to the raw disk gadgets, the FILESYSTEMIO_OPTIONS  parameter is most effective for filesystems.

Q15. What Is Asm?

               In Oracle Database 10g/11g there are two varieties of instances: database and ASM instances. The ASM example, which is normally named +ASM, is started with the INSTANCE_TYPE=ASM init.Ora parameter. This parameter, when set, indicators the Oracle initialization recurring to start an ASM example and now not a fashionable database instance. Unlike the usual database instance, the ASM example consists of no bodily documents; along with logfiles, controlfiles or datafiles, and most effective calls for a few init.Ora parameters for startup.

               Upon startup, an ASM instance will spawn all of the primary heritage approaches, plus a few new ones which can be specific to the operation of ASM. The STARTUP clauses for ASM times are similar to those for database instances. For instance, RESTRICT prevents database instances from connecting to this ASM example. NOMOUNT starts up an ASM instance without mounting any disk institution. MOUNT alternative virtually mounts all described diskgroups

              For RAC configurations, the ASM SID is +ASMx example, where x represents the example variety.

Q16. How Many Asm Diskgroups Can Be Created Under One Asm Instance?

ASM imposes the subsequent limits:

63 disk organizations in a storage device

10,000 ASM disks in a garage gadget

Two-terabyte maximum storage for every ASM disk (non-Exadata)

Four-petabyte most garage for every ASM disk (Exadata)

forty-exabyte maximum storage for each storage gadget

1 million documents for each disk institution

ASM report size limits (database restrict is 128 TB):

External redundancy most record size is one hundred forty PB.

Normal redundancy most document size is forty two PB.

High redundancy most record length is 15 PB.

Q17. Can My Rdbms And Asm Instances Run Different Versions?

Yes. ASM can be at a higher version or at decrease version than its consumer databases. There’s two:

components of compatiblity: Software compatibility

Diskgroup compatibility attributes: well suited.Asm, well matched.Rdbms.

Q18. What Are The Performance Views In An Oracle Rac Environment?

We have v$ perspectives which are instance precise. In addition we've GV$ views called as worldwide views that has an INST_ID column of numeric records kind.GV$ perspectives reap statistics from character V$ views.

 

Q19. Where Do I Run My Database Listener From; I.E., Asm Home Or Db Home?

It is suggested to run the listener from the ASM HOME. This is mainly important for RAC env, for the reason that listener is a node-stage useful resource. In this config, you may create additional [user] listeners from the database homes as wished.

 

Q20. I'm Going To Do Add Disks To My Asm Diskgroup, How Long Will This Rebalance Take?

Rebalance time is heavily pushed by using the three items:

1) Amount of statistics presently in the diskgroup

2) IO bandwidth available on the server

3) ASM_POWER_LIMIT or Rebalance Power Level

Q21. List Key Benefits Of Asm?

Stripes files instead of logical volumes

Provides redundancy on a document basis

Enables on line disk reconfiguration and dynamic rebalancing

Reduces the time considerably to resynchronize a trient failure through monitoring adjustments whilst disk is offline

Provides adjustable rebalancing velocity

Is cluster-aware

Supports reading from reflected copy in preference to primary copy for prolonged clusters

Is robotically hooked up as part of the Grid Infrastructure

Q22. Do You Know Another Cluster Vendor?

HP Tru64 Unix, Veritas, Microsoft

Q23. What Is A Cfs?

A cluster File System (CFS) is a document system that can be accessed (study and write) by means of all participants in a cluster on the identical time. This implies that all members of a cluster have the same view.

Q24. Describe The Oracle Real Application Clusters Architecture?

Oracle RAC consists of a database this is represented in a clustered way inside the architecture.

The cluster is the collection or pool of unbiased servers that make up one unmarried system.

Cluster structure offers extra flexibility to control and follow a modular incremental approach to enhance the fault mistakes and provide an incremental device.

This architecture provides the maximum safety in phrases of ensuring excessive availability of the assets to the users.

It affords the assets on call for and provides hardware structure such that a single factor of failure is being eliminated.

The structure presents the decoupling of the Oracle example just like the process and reminiscence which can be walking at the server from the Oracle database.

Q25. What Kind Of Storage We Can Use For The Shared Clusterware Files?

OCFS (Release 1 or 2)

raw gadgets

third celebration cluster document machine together with GPFS or Veritas

Q26. Explain The Hardware Architecture Used In Oracle Rac?

The Hardware Architecture of the Oracle RAC clusters provides a shared structure with the server pools and permits all of the storage gadgets to be shared.

Hardware Architecture helps exclusive varieties of garage networks like Network connected storage (NAS), Storage Area Network (SAN) and SCSI disks.

Hardware architecture is such that it affords suitable alternatives for the garage swimming pools and device that offers scalability and flexibility to the general device.

The architecture ought to comprise the enter and output for the software that need to be advanced after which the device could have extra scalability.

Hardware architecture supports greater utility to be brought inside the server pool and lets in higher integration of services.

Q27. Would It Be Better To Use Bigfile Tablespaces, Or Standard Tablespaces For Asm?

The use of Bigfile tablespaces has no relating ASM (or vice versa). In truth most database object associated selections are trparent to ASM.

Q28. What Are The File Types That Asm Support And Keep In Disk Groups?

Control documents

Flashback logs

Data Pump sell off units

Data files

DB SPFILE

Data Guard configuration

Temporary information files

RMAN backup sets

Change tracking bitmaps

Online redo logs

RMAN information record copies

OCR documents

Archive logs

Trport statistics files

ASM SPFILE

Q29. What Is The Use Of Ocr?

Oracle Clusterware manages CRS sources based totally at the configuration information of CRS sources stored in OCR (Oracle Cluster Registry).

Q30. What Kind Of Storage We Can Use For The Rac Database Storage?

OCFS (Release 1 or 2)

ASM

uncooked gadgets

0.33 celebration cluster report system which include GPFS or Veritas

Q31. What Init.Ora Parameters Does A User Need To Configure For Asm Instances?

The default parameter settings paintings perfectly for ASM. The simplest parameters needed for 11g ASM:

PROCESSES*

ASM_DISKSTRING*

ASM_DISKGROUPS

INSTANCE_TYPE

Q32. How Does Database Connects To Asm Instance?

The database communicates with ASM example the use of the ASMB (umblicus procedure) manner. Once the database obtains the necessary extents from quantity map, all database IO going  ahead is processed via by way of the database methods, bypassing ASM. Thus we say ASM isn't definitely inside the IO course. So, the question how will we make ASM pass quicker…..You don’t should.

Q33. Why Oracle Recommends Two Disk Groups?

Oracle recommends two diskgroups to offer a balance of manageability, usage, and overall performance.

 

Q34. How Do We Remove Asm From An Oracle Rac Environment?

We want to prevent and delete the instance in the node first in interactive or silent mode. After that ASM may be eliminated the use of srvctl tool as follows:

srvctl forestall asm -n node_name

srvctl eliminate asm -n node_name

We can affirm if ASM has been removed by means of issuing the subsequent command:

srvctl config asm -n node_name

Q35. Is It Possible To Unplug An Asm Disk Group From One Platform And Plug Into A Server On Another Platform (for Example, From Solaris To Linux)?

No. Cross-platform disk group migration not supported. To pass datafiles between endian-ness platforms, you want to apply XTTS, Datapump or Streams.

Q36. How Does Asm Work With Multipathing Software?

It works excellent! Multipathing software program is at a layer lower than ASM, and therefore is trparent.

You may additionally want to modify ASM_DISKSTRING to specify handiest the direction to the multipathing pseudo gadgets.

Q37. What Is An Ocfs2?

The OCFS2 is the Oracle (model 2) Cluster File System which may be used for the Oracle Real Application Cluster.

Q38. What Is The Best Lun Size For Asm?

There isn't any satisfactory length! In maximum instances the garage crew will dictate to you based totally on their standardized LUN size. The ASM administrator merely has to speak the ASM Best Practices and application  traits to storage folks :

• Need similarly sized / overall performance LUNs

• Minimum of 4 LUNs

• The ability requirement

• The workload characteristic (random r/w, sequential r/w) & any reaction time SLA

Using this info , and their standards, the storage folks have to construct a pleasing LUN institution set for you.

 

Q39. What Is The Main Purpose Of Oracle Real Application Clusters (rac)?

Oracle Real Application (RAC) offers the interaction of executable record with the Oracle database.

It allows the walking of any packaged or custom constructed utility with the Oracle database this is strolling on a server pool.

It presents very high level of availability, flexibility and scalability to run the application and keep it to the database.

It creates the database such that if the pool fails then the database is continued to run from the ultimate servers and the load can be distributed.

It makes it simpler for the administrator to maintain many servers on the same time by means of load-balancing strategies and offering provision to feature increasingly servers whilst the burden increases.

Q40. Where Are The Database Software Files Stored On A Rac Environment?

The base software is established on every node of the cluster and the database storage at the shared disks.

Q41. In 11g Rac We Want To Separate Asm Admins From Dbas And Create Different Users And Groups. How Do We Set This Up?

For rationalization

• Separate Oracle Home for ASM and RDBMS.

• RDBMS instance connects to ASM using OSDBA group of the ASM instance.

Thus, software owner for each RDBMS example connecting to ASM need to be a member of ASM's OSDBA group.

• Choose a exclusive OSDBA group for ASM instance (asmdba) than for RDBMS instance (dba)

• In 11g, ASM administrator must be member of a separate SYSASM group to separate ASM Admin and DBAs.

Q42. How Does The Database Interact With The Asm Instance And How Do I Make Asm Go Faster?

ASM is not inside the I/O course so ASM does not impede the database record get admission to. Since the RDBMS instance is appearing raw I/O, the I/O is as rapid as feasible.

Q43. What Is Scan?

Single Client Access Name (SCAN) is s a brand new Oracle Real Application Clusters (RAC) 11g Release 2 characteristic that gives a unmarried name for customers to get entry to an Oracle Database walking in a cluster. The benefit is clients the use of SCAN do not need to trade in case you add or remove nodes within the cluster.

 

Q44. How Is Clustered Database Important In Oracle Rac Architecture?

Clustered database is just like a single database accessed by way of multiple times which might be going for walks on the server.

The times are being run separately or in my view on the server pool and while the needs rise they're shifted to gather more space according to the necessities.

Clustered database provides dynamic get entry to to the database and on the call for of extra sources they may be introduced to the server pool.

If one cluster is taking on the load then that load is shared among different clusters walking at the server and the utility offerings are provided in a far quicker and higher manner.

This also lets in the adding of extra resources dynamically to the server pool and not using a downtime and the application starts going for walks quickly it is deployed on the server.