Interview Q and A for Oracle RAC Part - 5

271. What is difference between RAC ip addresses ?

Public IP adress is the normal IP address typically used by DBA and SA to manage storage, system and database. Public IP addresses are reserved for the Internet.

Private IP address is used only for internal clustering processing (Cache Fusion) (aka as interconnect). Private IP addresses are reserved for private networks.

VIP is used by database applications to enable fail over when one cluster node fails. The purpose for having VIP is so client connection can be failover to surviving nodes in case there is failure

272. Can application developer access the private ip ?

No. private IP address is used only for internal clustering processing (Cache Fusion) (aka as interconnect)

http://rajeevjhaoracle.wordpress.com/2012/01/02/oracle-rac-interview-question-answer/

273. Where are the Clusterware files stored on a RAC environment?
 The Clusterware is installed on each node (on an Oracle Home) and on the shared disks (the voting disks and the CSR file) 

274. Where are the database software files stored on a RAC environment? 
 The base software is installed on each node of the cluster and the database storage on the shared disks. 

275. What kind of storage we can use for the shared Clusterware files?
 - OCFS (Release 1 or 2)
- raw devices
- third party cluster file system such as GPFS or Veritas 

276. What kind of storage we can use for the RAC database storage?
 - - OCFS (Release 1 or 2)
- ASM
- raw devices
- third party cluster file system such as GPFS or Veritas 

277. What is a CFS?
 - A cluster File System (CFS) is a file system that may be accessed (read and write) by all members in a cluster at the same time. This implies that all members of a cluster have the same view. 

278. What is an OCFS2?
 - The OCFS2 is the Oracle (version 2) Cluster File System which can be used for the Oracle Real Application Cluster. 

279. What are the dependencies between OCFS and ASM in Oracle Database 10g ?

In an Oracle RAC 10g environment, there is no dependency between Automatic Storage Management (ASM) and Oracle Cluster File System (OCFS). OCFS is not required if you are using Automatic Storage Management (ASM) for database files. You can use

OCFS on Windows( Version 2 on Linux ) for files that ASM does not handle - binaries (shared oracle home), trace files, etc. Alternatively, you could place these files on local file systems even though it's not as convenient given the multiple locations.

If you do not want to use ASM for your database files, you can still use OCFS for database files in Oracle Database 10g.

280. Which files can be placed on an Oracle Cluster File System?
 - - Oracle Software installation (Windows only)
- Oracle files (controlfiles, datafiles, redologs, files described by the bfile datatype)
- Shared configuration files (spfile)
- OCR and voting disk
- Files created by Oracle during runtime
Note: There are some platform specific limitations. 

281. Do you know another Cluster Vendor?
 - HP Tru64 Unix, Veritas, Microsoft 

282. How is possible to install a RAC if we don’t have a CFS?
 - This is possible by using a raw device. 

283. What is a raw device?
 - A raw device is a disk drive that does not yet have a file system set up. Raw devices are used for Real Application Clusters since they enable the sharing of disks. 

284. What is a raw partition?
 - A raw partition is a portion of a physical disk that is accessed at the lowest possible level. A raw partition is created when an extended partition is created and logical partitions are assigned to it without any formatting. Once formatting is complete, it is called cooked partition. 

285. When to use CFS over raw?
 A CFS offers:
- Simpler management
- Use of Oracle Managed Files with RAC
- Single Oracle Software installation
- Autoextend enabled on Oracle datafiles
- Uniform accessibility to archive logs in case of physical node failure
- With Oracle_Home on CFS, when you apply Oracle patches CFS guarantees that the updated Oracle_Home is visible to all nodes in the cluster.
Note: This option is very dependent on the availability of a CFS on your platform. 

286. When to use raw over CFS?
- Always when CFS is not available or not supported by Oracle.
- The performance is very, very important: Raw devices offer best performance without any intermediate layer between Oracle and the disk.
Note: Autoextend fails on raw devices if the space is exhausted. However the space could be added online if needed. 

287. What CRS is?
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. 

288. Why we need to have configured SSH or RSH on the RAC nodes?
SSH (Secure Shell,10g+) or RSH (Remote Shell, 9i+) allows “oracle” UNIX account connecting to another RAC node and copy/ run commands as the local “oracle” UNIX account. 

289. Is the SSH, RSH needed for normal RAC operations?
No. SSH or RSH are needed only for RAC, patch set installation and clustered database creation. 

290. Do we have to have Oracle RDBMS on all nodes?
Each node of a cluster that is being used for a clustered database will typically have the RDBMS and RAC software loaded on it, but not actual data files (these need to be available via shared disk). 

291. What are the restrictions on the SID with a RAC database? Is it limited to 5 characters? 

The SID prefix in 10g Release 1 and prior versions was restricted to five characters by install/ config tools so that an ORACLE_SID of up to max of 5+3=8 characters can be supported in a RAC environment. The SID prefix is relaxed up to 8 characters in 10g Release 2, see bug 4024251 for more information. 

With Oracle RAC 11g Release 2, SIDs in Oracle RAC with Policy Managed database are dynamically allocated by the system when the instance starts. This supports a dynamic grid infrastructure which allows the instance to start on any server in the cluster.

292. Does Real Application Clusters support heterogeneous platforms?
The Real Application Clusters do not support heterogeneous platforms in the same cluster. Enterprise Manager Grid Control supports heterogeneous platforms. We do support machines of different speeds and size in the same cluster. In an active data-sharing environment, like Oracle RAC, we do not support machines having different chip architectures.
293. Are there any issues for the interconnect when sharing the same switch as the public network by using VLAN to separate the network?
RAC and Clusterware deployment best practices suggests that the interconnect (private connection) be deployed on a stand-alone, physically separate, dedicated switch. On big network the connections could be instable. 

Many customers, however, have consolidated these stand-alone switches into larger managed switches. A consequence of this consolidation is a merging of IP networks on a single shared switch, segmented by VLANs. There are caveats associated with such deployments.

The Oracle RAC cache fusion protocol exercises the IP network more rigorously than non-RAC Oracle databases. The latency and bandwidth requirements as well as availability requirements of the Oracle RAC / Oracle Clusterware interconnect IP network are more in-line with high performance computing.

Deploying the Oracle RAC / Oracle Clusterware interconnect on a shared switch, segmented by a VLAN may expose the interconnect links to congestion and instability in the larger IP network topology.

If deploying the interconnect on a VLAN, there should be a 1:1 mapping of the VLAN to a non-routable subnet and the VLAN should not span multiple VLANs (tagged) or multiple switches.

Deployment concerns in this environment include Spanning Tree loops when the larger IP network topology changes, Assymetric routing that may cause packet flooding, and lack of fine grained monitoring of the VLAN/port.

294. What is the Load Balancing Advisory?
To assist in the balancing of application workload across designated resources, Oracle Database 10g Release 2 provides the Load Balancing Advisory. This Advisory monitors the current workload activity across the cluster and for each instance where a service is active; it provides a percentage value of how much of the total workload should be sent to this instance as well as service quality flag. The feedback is provided as an entry in the Automatic Workload Repository and a FAN event is published. The easiest way for an application to take advantage of the load balancing advisory, is to enable Runtime Connection Load Balancing with an

integrated client.

295. How many nodes are supported in a RAC Database?
With 10g Release 2, we support 100 nodes in a cluster using Oracle Clusterware, and 100 instances in a RAC database. Currently DBCA has a bug where it will not go beyond 63 instances. There is also a documentation bug for the max-instances parameter. With 10g Release 1 the Maximum is 63. 

296. How many nodes can be had in an HP-UX/Solaris/AIX/Windows/Linux cluster?

The number of nodes supported is not limited by Oracle, but more generally by the clustering software/hardware in question.

When using solely Oracle Clusterware: 63 nodes (Oracle 9i or Oracle RAC 10g Release 1) With 10g Release 2, the maximum nodes is 100

When using a third party clusterware:

Sun: 8

HP UX: 16

HP Tru64: 8

IBM AIX:

* 8 nodes for Physical Shared (CLVM) SSA disk

* 16 nodes for Physical Shared (CLVM) non-SSA disk

* 128 nodes for Virtual Shared Disk (VSD)

* 128 nodes for GPFS

* Subject to storage subsystem limitations

Veritas: 8-16 nodes (check w/ Veritas)

For 3rd party vendor clusterware, please check with the vendor.

297. What is the Cluster Verification Utiltiy (cluvfy)? What are its objectives and features?

CVU is a utility that is distributed with Oracle Clusterware. It was developed to assist in the installation and configuration of Oracle Clusterware as well as RAC. CVU will verify all the important components that are needed at different stages in configuring a RAC environment. The wide domain of verification provided by CVU ranges from initial hardware setup through fully operational cluster for RAC deployment and covers all the intermediate stages of installation and configuration of various components. The command line tool is cluvfy. Cluvfy is a non-intrusive utility and will not adversely affect the system or operational stack.

298. What versions of the database can I use the cluster verification utility (cluvfy) with?
The cluster verification utility is release with Oracle Database 10g Release 2 but can also be used with Oracle Database 10g Release 1. 

299. If I am using Vendor Clusterware such as Veritas, IBM, Sun or HP, do I still need Oracle Clusterware to run Oracle RAC 10g or Oracle RAC 11g?
Yes. When certified, you can use Vendor Clusterware however you must still install and use Oracle Clusterware for RAC. Best Practice is to leave Oracle Clusterware to manage RAC. For details see Metalink Note 332257.1 and for Veritas SFRAC see 397460.1. 

300. What files can I put on Linux OCFS2?
  For optimal performance, you should only put the following files on Linux OCFS2:
- Datafiles
- Control Files
- Redo Logs
- Archive Logs
- Shared Configuration File (OCR)
- Voting File
- SPFILE
For optimal performance, you should only put the following files on Linux OCFS:

- Datafiles

- Control Files

- Redo Logs

- Archive Logs

- SPFILE

Oracle Clusterware files OCR and Voting Disk can be put on OCFS2 however Best Practice is to put them on raw or block devices.

301. Is it possible to use ASM for the OCR and voting disk?
Yes. As of Oracle Real Application Clusters 11g Release 2, the OCR and Voting Disks can be stored in ASM.

This is the recommended best practice for this release.

For releases prior to 11g Release 2, the OCR and voting disk must be on RAW devices or CFS (cluster filesystem).

RAW devices (or block devices on Linux) is the best practice for Oracle RAC 10g or Oracle RAC 11g Release 1.

302. Can I change the name of my cluster after I have created it when I am using Oracle Clusterware?
No, you must properly deinstall Oracle Clusterware and then re-install. To properly de-install Oracle Clusterware, you MUST follow the directions in the Installation Guide. This will ensure the ocr gets cleaned out.

303. What the O2CB is?
The O2CB is the OCFS2 cluster stack. OCFS2 includes some services. These services must be started before using OCFS2 (mount/ format the file systems). 

304. What is the recommended method to make backups of a RAC environment?
RMAN to make backups of the database, dd to backup your voting disk and hard copies of the OCR file. 

305. What is the minimum number of instances you need to have in order to create a RAC?
You can create a RAC with just one server. 

306. What was RAC previous name before it was called RAC?
  OPS: Oracle Parallel Server 

307. What is the difference between normal views and RAC views?
A RAC view has the prefix ‘G’. For example, GV$SESSION instead of V$SESSION 

308. Which command will we use to manage (stop, start) RAC services in command-line mode?
  srvctl 

309. How many alert logs exist in a RAC environment?
  One for each instance. 

310. How do you backup voting disk
  #dd if=voting_disk_name of=backup_file_name 

311. How do you backup the OCR
 There is an automatic backup mechanism for OCR. The default location is : $ORA_CRS_HOME\cdata\"clustername"\
To display backups :
#ocrconfig -showbackup
To restore a backup :
#ocrconfig -restore
With Oracle RAC 10g Release 2 or later, you can also use the export command:
#ocrconfig -export -s online, and use -import option to restore the contents back.
With Oracle RAC 11g Release 1, you can do a manaual backup of the OCR with the command:
# ocrconfig -manualbackup
The automatic backup mechanism keeps upto about a week old copy. So, if you want to retain a backup copy more than that, then you should copy that "backup" file to some other name.

OCR backup on Windows are absent. Only file in the backup directory istemp.ocr which would be the last backup. You can restore this mostrecent backup by using the command ocr -restore temp.ocr

If you want to take a logical copy of OCR at any time use : ocrconfig -export , and use -import option to restore the contents back.

312. What is the purpose of the ONS daemon?
The Oracle Notification Service (ONS) daemon is an daemon started by the CRS clusterware as part of the nodeapps. There is one ons daemon started per clustered node. The ONS daemon receive a subset of published clusterware events via the local evmd and racgimon clusterware daemons and forward those events to application subscribers and to the local listeners.
This in order to facilitate:
a. the FAN or Fast Application Notification feature or allowing applications to respond to database state changes.
b. the 10gR2 Load Balancing Advisory, the feature that permit load balancing accross different rac nodes dependent of the load on the different nodes. The rdbms MMON is creating an advisory for distribution of work every 30seconds and forward it via racgimon and ONS to listeners and applications.

313. Is crossover cable supported as an interconnect with RAC on any platform ?

NO. CROSS OVER CABLES ARE NOT SUPPORTED. The requirement is to use a switch:

Detailed Reasons:

1) cross-cabling limits the expansion of RAC to two nodes

2) cross-cabling is unstable:

a) Some NIC cards do not work properly with it. They are not able to negotiate the DTE/DCE clocking, and will thus not function. These NICS were made cheaper by assuming that the switch was going to have the clock. Unfortunately there is no way to know which NICs do not have that clock.

b) Media sense behaviour on various OS's (most notably Windows) will bring a NIC down when a cable is disconnected. Either of these issues can lead to cluster instability and lead to ORA-29740 errors (node evictions).

Due to the benefits and stability provided by a switch, and their afforability ($200 for a simple 16 port GigE switch), and the expense and time related to dealing with issues when one does not exist, this is the only supported configuration.

From a purely technology point of view Oracle does not care if the customer uses cross over cable or router or switches to deliver a message. However, we know from experience that a lot of adapters misbehave when used in a crossover configuration and cause a lot of problems for RAC. Hence we have stated on certify that we do not support crossover cables to avoid false bugs and finger pointing amongst the various parties: Oracle, Hardware vendors, Os vendors etc...

314. How do users connect to database in an Oracle RAC environment

Users can access a RAC database using a client/server configuration or through one or more middle tiers ,with or without connection pooling.Users can use oracle services feature to connect to database.

315. Where can we apply FAN UP and DOWN events

FAN UP and FAN DOWN events can be applied to instances,services and nodes.

316. State the use of FAN events in case of a cluster configuration change

During times of cluster configuration changes,Oracle RAC high availability framework publishes a FAN event immediately when a state change occurs in the cluster.So applications can receive FAN events and react immediately.This prevents applications from polling database and detecting a problem after such a state change.

317. Why should we have separate ORACLE_HOME for ASM instances

It is a good practice to have ASM home seperate from the database home(ORACLE_HOME).This helps in upgrading and patching ASM and the Oracle database software independent of each other.Also,we can deinstall the Oracle database software independent of the ASM instance.

318. What is rolling upgrade

It is a new ASM feature from Database 11g.ASM instances in Oracle database 11g release(from 11.1) can be upgraded or patched using rolling upgrade feature. This enables us to patch or upgrade ASM nodes in a clustered environment without affecting database availability.During a rolling upgrade we can maintain a functional cluster while one or more of the nodes in the cluster are running in different software versions.

319. Can rolling upgrade be used to upgrade from 10g to 11g database

No,it can be used only for Oracle database 11g releases(from 11.1).

320. Can the DML_LOCKS and RESULT_CACHE_MAX_SIZE be identical on all instances?

These parameters can be identical on all instances only if these parameter values are set to zero.

321. How does a Oracle Clusterware manage CRS resources

Oracle clusterware manages CRS resources based on the configuration information of CRS resources stored in OCR(Oracle Cluster Registry).

322. Give the usage of srvctl:

srvctl start instance -d db_name -i "inst_name_list" [-o start_options]

srvctl stop instance -d name -i "inst_name_list" [-o stop_options]

srvctl stop instance -d rac -i "rac3,rac4" -o immediate

srvctl start database -d name [-o start_options]

srvctl stop database -d name [-o stop_options]

srvctl start database -d rac -o mount

323. I have changed my spfile with alter system set <parameter_name>=.... scope=spfile. The spfile is on ASM storage and the database will not start.

How to recover:

In $ORACLE_HOME/dbs

. oraenv<instance_name>

sqlplus "/ as sysdba"

startup nomount

create pfile='recoversp' from spfile

/

shutdown immediate

quit

Now edit the newly created pfile to change the parameter to something sensible.

Then:

sqlplus "/ as sysdba"

startup pfile='recoversp' (or whatever you called it in step one).

create spfile='+DATA/GASM/spfileGASM.ora' from pfile='recoversp' / N.B.The name of the

spfile is in your original init<instance_name>.ora so adjust to suit shutdown immediate

startup

quit

324. Is it supported to install Oracle Clusterware and RAC as different users.

Yes, Oracle Clusterware and RAC can be installed as different users. The Oracle Clsuterware user and the RAC user must both have OSDBA as their primary group, and they should both have OINSTALL as a secondary group.

325. WARNING: No cluster interconnect has been specified. I get this error starting my RAC database, what do I do?

This simply means that you neither have a cluster_interconnects parameter set for the database, nor was there any cluster interconnect specification found in the OCR, so that the private interconnect is picked at random by the database, and hence the warning. You can either set the cluster_interconnects parameter in the initialization file (spfile / pfile) of the datbase to specify a private interconnect IP, OR you can use "oifcfg setif" (type "oifcfg" for help) to classify a certain network for as the cluster interconnect network.

$ oifcfg getif

eth0 138.2.236.0 global public

eth2 138.2.238.0 global cluster_interconnect

Note that oifcfg enables you to specify "local" as well as "global" settings. With Oracle Clusterware 10g Rel. 1 and Rel. 2 as well as Oracle Clusterware 11g Rel. 1, it is, however, only supported to use global settings. If the hardware (network interface) meant to be used for the interconnect is not the same on all nodes in the cluster, the configuration needs to be changed on the hardware / OS level accordingly.

326. I want to use rconfig to convert a single instance to Oracle RAC but I am using raw devices in

Oracle RAC. Does rconfig support RAW ?

No. rconfig supports ASM and shared file system only.

327. Can we designate the place of archive logs on both ASM disk and regular file system, when we use SE RAC?

Yes, - customers may want to create a standby database for their SE RAC database so placing the archive logs additionally outside ASM is OK.

328. Why does netca always creates the listener which listens to public ip and not VIP only?

This is for backward compatibility with existing clients: consider pre-10g to 10g server upgrade. If we made upgraded listener to only listen on VIP, then clients that didn't upgrade will not be able to reach this listener anymore.

329. What Application Design considerations should I be aware of when moving to Oracle RAC?

 The general principals are that fundamentally no different design and coding practices are required for RAC however application flaws in execution or design have a higher impact in RAC. The performance and scalability in RAC will be more sensitive to bad plans or bad schema design. Serializing contention makes applications less scalable. If your customer uses standard SQL and schema tuning, it solves > 80% of performance problems .

Some of the scaleability pitfalls they should look for are:

* Serializing contention on a small set of data/index blocks

-->monotonically increasing key

-->frequent updates of small cached tables

-->segment without automatic segment space management (ASSM) or Free List Group (FLG)

* Full table scans

--> Optimization for full scans in 11g can save CPU and latency

* Frequent invalidation and parsing of cursors

--> Requires data dictionary lookups and synchronizations

* Concurrent DDL ( e.g. truncate/drop )

Look for:

* Indexes with right-growing characteristics

--> Use reverse key indexes

--> Eliminate indexes which are not needed

* Frequent updated and reads of ısmallı tables

-->ısmallı=fits into a single buffer cache

--> Use Sparse blocks ( PCTFREE 99 ) to reduce serialization

* SQL which scans large amount of data

--> Perhaps more efficient when parallelized

--> Direct reads do not need to be globally synchronized ( hence less CPU for global cache )

330. What kind of HW components do you recommend for the interconnect?

The general recommendation for the interconnect is to provide the highest bandwith interconnect,together with the lowest latency protocol that is available for a given platform. In practice, GigabitEthernet with UDP has proven sufficient in every case it has been implemented, and tends to be the lowest common denominator across platforms.

331. Is it difficult to transition (migrate) from Single Instance to Oracle RAC?

If the cluster and the cluster software are not present, these components must be installed and configured. The Oracle RAC option must be added using the Oracle Universal Installer, which necessitates the existing DB instance must be shut down. There are no changes necessary on the user data within the database.However, a shortage of freelists and freelist groups can cause contention with header blocks of tables and indexes as multiple instances vie for the same block. This may cause a performance problem and require data partitioning. However, the need for these changes should be rare.

Recommendation: apply automatic space segment management to perform these changes automatically. The free space management will replace the freelists and freelist groups and is better. The database requires one Redo thread and one Undo tablespace for each instance, which are easily added with SQL commands or with Enterprise Manager tools.

NOTE: With ORacle RAC 11g Release 2, you do not neet to pre-create redo threads or undo tablespaces if you are using Oracle Managed Files (EG ASM). Datafiles will need to be moved to either a clustered file system (CFS) so that all nodes can access them.

Oracle recommends the use of Automatic Storage Management (ASM) Also, the MAXINSTANCES parameter in the control file must be greater than or equal to number of instances you will start in the cluster.

With Oracle Database 10g Release 2, $ORACLE_HOME/bin/rconfig tool can be used to convert Single instance database to RAC. This tool takes in a xml input file and convert the Single Instance database whose information is provided in the xml. You can run this tool in "verify only" mode prior to performing actual conversion. This is documented in the Oracle RAC Admin book and a sample xml can be found $ORACLE_HOME/assistants/rconfig/sampleXMLs/ConvertToRAC.xml. This tool only supports databases

using a clustered file system or ASM. You cannot use it with raw devices. Grid Control 10g Release 2 provides a easy to use wizard to perform this function.

4456047>> (shutdown immediate hangs) as you convert is release noted as well.

Oracle Enterprise Manager includes workflows to assiste with migrations. (I.E. Migrating to ASM, Creating Standby, Converting Standby to RAC etc) The migration is automated in Enterprise Manager Grid Control 10.2.0.5.

332. What is Standard Edition RAC?

As of Oracle Database 10g, a customer who has purchased Standard Edition is allowed to use the Oracle RAC option within the limitations of Standard Edition(SE). For licensing restrictions you should read the Oracle Database License Doc. At a high level this means that you can have a max of 4 sockets in the cluster, you must use ASM for all database files. As of Oracle Database 11g Release 2, ASM includes ACFS (a cluster file system). ASM Cluster File System (ACFS) or a local OS file system must be used to store all nondatabase files including Oracle Home, Application and system files, and User files

NOTE: 3rd party clusterware and clustered file systems(other than ASM) are not supported. This includes OCFS and OCFS2.

Here is the text from the appropriate footnote in the Price List (as of Jan2010, please check price list for any changes):

Oracle Database Standard Edition can only be licensed on servers that have a maximum capacity of 4 sockets. If licensing by Named User Plus, the minimum is 5 Named User Plus licenses. Oracle Database Standard Edition, when used with Oracle Real Application Clusters, may only be licensed on a single cluster of servers supporting up to a total maximum capacity of 4 sockets.

333. When configuring the NIC cards and switch for a GigEInterconnect should it be set to FULL or Half duplex in RAC?

 You've got to use Full Duplex, regardless of RAC or not, but for all network communication. HalfDuplex means you can only either send OR receive at the same time.

334. Is it a good idea to add anti-virus software to my RAC cluster?

For customers who choose to run anti-virus (AV) software on their database servers, they should be aware that the nature of AV software is that disk IO bandwidth is reduced slightly as most AV software checks disk writes/reads. Also, as the AV software runs, it will use CPU cycles that would normally be consumed by other server processes (e.g your database instance). As such,

databases will have faster performance when not using AV software. As some AV software is known to lock the files whilst is scans then it is a good idea to exclude the OracleDatafiles/controlfiles/logfiles from a regular AV scan

335. Can I use RAC in a distributed transaction processing  environment?

YES. Best practices is to have all tightly coupled branches of a distributed transaction running on an Oracle RAC database must run on the same instance. Between transactions and between services, transactions can be load balanced across all of the database instances.

Prior to Oracle RAC 11g, you must use services to manage DTP environments. By defining the DTP property of a service, the service is guaranteed to run on one instance at a time in an Oracle RAC database. All global distributed transactions performed through the DTP service are ensured to have their tightly-coupled branches running on a single Oracle RAC instance.

Oracle RAC 11g provides transparent support for XA global transactions in an Oracle RAC environment and you do not need to use DTP services.

336. Does Oracle support Oracle RAC in Solaris containers (a.k.a. Solaris Zones)?

YES for Oracle RAC 10g Rel. 2 onwards. While Global containers have been supported for a while, Oracle added support for local containers recently after the local containers were extended to allow direct hardware modification.

Lifting this restriction allow Oracle Clusterware to operate on hardware resources such as the network for the Oracle VIP directly, enabling Oracle RAC to run in local containers.

337. Is relink required for CRS_HOME/Clusterware home after OS upgrade?

Oracle Clusterware binaries cannot be relinked on shiphomes. So to answer your question no,there is not need to relink Oracle Clusterware binaries.

In 11.2, there are some executables in the GRID home that can and should be re-linked after an OS upgrade. The procedure to do this is:
#> cd GI_HOME/crs/install
#> perl rootcrs.pl -unlock
As the grid infrastructure for a cluster owner:
$> export ORACLE_HOME=Grid_home
$> $GI_HOME/bin/relink
As root again:
# cd Grid_home/crs/install

# perl rootcrs.pl -patch

In 10g and 11.1, Oracle Clusterware binaries cannot be relinked. However, the client shared libraries on that home can be relinked, in most cases there should not be a need to relink them. See Note:743649.1 on how to do that.

338. Does changing uid or gid of the Oracle User affect OracleClusterware?

There are a lot of files in the Oracle Clusterware home and outside of the Oracle Clusterwarehome that are chgrp'ed to the appropriate groups for security and appropriate access. The filesystem records the uid (not the username), and so if you exchange the names, now the files are owned by the wrong group.

339. Can I run more than one clustered database on a single RACcluster?

You can run multiple databases in a RAC cluster, either one instance per node (w/ different databases having different subsets of nodes in a cluster), or multiple instances per node (all databases running across all nodes) or some combination in between. Running multiple instances per node does cause memory and resource fragmentation, but this is no different from running multiple instances on a single node in a single instance environment which is quite common. It does provide the flexibility of being able to share CPU on the node, but the Oracle Resource Manager will not currently limit resources between multiple instances on one node. You will need to use an OS level resource manager to do this.

340. Where can I find a list of supported solutions to ensure NIC availability (for the interconnect) per platform?

   IBM AIX - available solutions:

Etherchannel (OS based)

HACMP based network failover solution

More information: Metalink Note 296856.1

HP HP/UX - available solutions:

APA - Auto Port Aggregation (OS based)

MC/Serviceguard based network failover solution

Combination of both solutions

More information: Metalink Note 296874.1 and Auto Port Aggregation (APA) Support Guide

Sun Solaris - available solutions:

Sun Trunking (OS based)

Sun IPMP (OS based)

Sun Cluster based network failover solution (IPMP based)

More information: Metalink Note 283107.1 - IPMP in general. When IPMP is used for the interconnect: Metalink Note 368464.1

Linux - available solutions:

Bonding

More information: Metalink Note 298891.1

Windows - available solutions:

Teaming

On Windows teaming solutions to ensure NIC availability are usually part of the network card driver.

Thus, they depend on the network card used.