RAC Best Practices on Linux

1
RAC Best Practices on Linux
Session id 40136

• Kirk McGowanTechnical Director RAC Pack
• Server Technologies
• Oracle Corporation

Roland KnappPrincipal Member Technical Staff
RAC Pack Server Technologies Oracle Corporation
2
Agenda

• Planning Best Practices
• Architecture
• Expectation setting
• Objectives and success criteria
• Project plan
• Implementation Best Practices
• Infrastructure considerations
• Installation/configuration
• Database creation
• Application considerations
• Operational Best Practices
• Backup Recovery
• Performance Monitoring and Tuning
• Production Migration

3
Planning

• Understand the Architecture
• Cluster terminology
• Functional basics
• HA by eliminating node Oracle as SPOFs
• Scalability by making additional processing
  capacity available incrementally
• Hardware components
• Private interconnect/network switch
• Shared storage/concurrent access/storage switch
• Software components
• OS, Cluster Manager, DBMS/RAC, Application
• Differences between cluster managers

4
RAC Hardware Architecture
Users
Network
Centralized Management Console
High Speed Switch or Interconnect
No Single Point Of Failure
Low Latency Interconnect ie. VIA or Proprietary
ClusteredDatabase Servers
Hub or Switch Fabric
Storage Area Network
Mirrored Disk Subsystem
5
RAC Software Architecture
Shared Data Model
Shared Disk Database
6
RAC on Linux HW SW Components
public network
Node1a
Node2a
more nodes higher availability
cluster interconnect
N3
N4
Nn
cache to cache
shared storage
concurrent access from every node scale out
redo log instance 1
redo log instance 2
control files
database files
7
Linux Cluster Hardware

• Cluster interconnects
• FastEthernet, Gigabit Ethernet
• Public networks
• Ethernet, FastEthernet, Gigabit Ethernet
• Memory, swap CPU Recommendations
• Each server should have a minimum of 512Mb of
  memory, at least 1Gb swap space, and two CPUs.
• Fiber Channel, SCSI, or NAS storage connectivity

8
Unbreakable Linux Distributions

• Red Hat Enterprise Linux AS and ES
• United Linux 1.0
• SuSE Linux Enterprise Server 8 (SuSE Linux AG)
• Conectiva Linux Enterprise Edition (Conectiva
  S.A.)
• SCO Linux Server 4.0 (The SCO Group)
• Turbolinux Enterprise Server 8 (Turbolinux)
• Oracle will support Oracle products running with
  other distributions but will not support the
  operating system.

9
RAC Certification for Unbreakable Linux

• Certification
• Enterprise class OS distribution (e.g. RH AS,
  United Linux 1.0)
• Clusterware (Oracle Cluster Manager only)
• Network Attached Storage (e.g. Network Appliance
  filers)
• Most SCSI and SAN storage are compatible
• 32 bit and 64 bit Itanium 2 Intel based servers
  are certified.
• For more details on software certification
  http//technet.oracle.com/support/metalink/content
  .html
• Discuss hardware configuration with your HW vendor

10
Linux IA64 requirements

• Operating System Requirements
• Red Hat Linux Advanced Server 2.1 operating
  system with kernel 2.4.18-e.14.ia64.rpm
• glibc 2.2.4-29
• Gnu gcc 2.96.0 release
• Linux Header Patch 2.4.18 (available from Intel)
• asynch libraries libaio-0.3.92-1
• (Oracle9i Release Notes Release 2 (9.2.0.2.0)
  for Linux Intel on Itanium (64-bit) Part No.
  B10567-02 )

11
Set Expectations Appropriately

• If your application will scale transparently on
  SMP, then it is realistic to expect it to scale
  well on RAC, without having to make any changes
  to the application code.
• RAC eliminates the database instance, and the
  node itself, as a single point of failure, and
  ensures database integrity in the case of such
  failures

12
Planning Define Objectives

• Objectives need to be quantified/measurable
• HA objectives
• Planned vs unplanned
• Technology failures vs site failures vs human
  errors
• Scalability Objectives
• Speedup vs scaleup
• Response time, throughput, other measurements
• Server/Consolidation Objectives
• Often tied to TCO
• Often subjective

13
Build your Project Plan

• Partner with your vendors
• Multiple stakeholders, shared success
• Build detailed test plans
• Confirm application scalability on SMP before
  going to RAC ? optimize first for single instance
• Address knowledge gaps and training
• Clusters, RAC, HA, Scalability, systems
  management
• Leverage external resources as required
• Establish strict System and Application Change
  control
• Apply changes to one system element at a time
• Apply changes to first to test environment
• Monitor impact of application changes on
  underlying system components
• Define Support mechanisms and escalation
  procedures

14
Agenda

• Planning Best Practices
• Architecture
• Expectation setting
• Objectives and success criteria
• Project plan
• Implementation Best Practices
• Infrastructure considerations
• Installation/configuration
• Database creation
• Application considerations
• Operational Best Practices
• Backup Recovery
• Performance Monitoring and Tuning
• Production Migration

15
Infrastructure Considerations

• Architecture/Design
• Eliminate SPOFs (Single Points of Failure)
• Workload Distribution (load balancing) strategy
• Systems management framework for monitoring and
  managing to SLAs
• Hardware/Software
• Processing nodes sufficient CPU to accommodate
  failure
• Scalable I/O Subsystem
• Use S.A.M.E.
• Private Interconnect
• Gige, UDP, switched
• Patch levels and certification

16
Impementation Flowchart
Configure HW
Install cluster manager 9.2.0.1
Create database
Configure private interconnect
Install Oracle 9.2.0.1
Install Unbreakable Linux
Install 9.2.0.3 cluster manager
Install Oracle 9.2.0.3
Configure storage and install OCFS
17
Installation Flowchart for Red Hat Linux AS 2.1
Boot
Use DRUID for Partition Setup
Account Configuration
Choose Language
Select Boot Loader
Select Graphic Mode
Select Keyboard Mouse
Configure Network
Boot Floppy Creation
Choose Advanced Server Option
Configure Timezone
Installation Complete / Reboot
18
Install tips for Red Hat Linux AS 2.1

• As documented in
• Tips and Techniques Install and Configure
  Oracle9i on Red Hat Linux Advanced Server by
  Deepak Patel, Oracle http//otn.oracle.com/tech/li
  nux/pdf/installtips_final.pdf
• Boot options
• Always use Advanced Server install. As needed
  install required packages. CD 1 to 3 has all rpm
  packages. CD 3 and 4 has source packages. CD 5
  includes docs.
• Memory
• Based on physical memory on machine smp or
  enterprise kernel is installed. (
  kernel and 4 GB enterprise kernel )
• Post Installation
• Add users, configure network and other
  administrative tasks after installation.

19
Install tips for United Linux 1.0

• You must install the latest UnitedLinux kernel
  update! Oracle was certified against an update
  kernel, the original UL-1.0 kernel is NOT
  certified!
• After installing United Linux 1.0, install
  Service Pack 2a from
• ftp//suse.us.oracle.com/pub/suse/i386/unitedlinux
  -1.0-iso/
• You will also need to have the basic developments
  tools installed, like make, gcc_old(2.95.3), and
  the binutils package.
• Full installation instructions
  ftp//ftp.suse.com/pub/suse/i386/supplementary/com
  mercial/Oracle/docs/920_sles8_install.pdf

20
Install tips for United Linux 1.0

• Install the orarun.rpm package from either the
  SP2 CD
• /UnitedLinux/i586/orarun-1.8-18.i586.r
  pm
• or from
• ftp//ftp.suse.com/pub/suse/i386/supplementary/com
  mercial/Oracle/sles-8/orarun.rpm
• orarun.rpm
• update kernel (ie. shmmax, shmmin)
• UDP settings (256K)
• Installs and configures hangcheck-timer

21
Prepare Linux Environment

• Follow these steps on EACH node of the cluster
• Set Kernel parameters in /etc/sysctl.conf
• Add hostnames to /etc/hosts file
• Establish file system or location for ORACLE_HOME
  (writable for oracle userid)
• Setup host equivalence for oracle userid (.rhosts)

22
Installation Flowchart for OCFS
Create partition on the primary node
Download the latest OCFS rpms from www.ocfs.org
Install the rpms on all nodes
Run ocfstool to format and mount your new
filesystem
Run ocfstool as root (configures
/etc/ocfs.conf) on all nodes
Mount the new filesystem on all nodes
Run load_ocfs (insmod will load ocfs.o) on all
nodes
Edit rc.local or equivalent add load_ocfs and
mount t ocfs 23
OCFS and Unbreakable Linux

• Redhat
• currently ships 4 flavors of the AS 2.1 kernel,
  viz., UP, SMP, Enterprise and Summit (IBM x440)
• Oracle provides a separate OCFS module for each
  of the kernel flavors
• Minor revisions of the kernel do not need a fresh
  build of ocfs
• e.g., ocfs built for e.12 will work for e.16,
  e.18, etc.
• United Linux
• United Linux ships 3 flavors of its kernel, for
  the 2.4.19-64GB-SMP, the 2.4.19-4GB and the
  2.4.19-4GB-SMP kernel
• OCFS 1.0.9 is supported on UL 1.0 Service Pack 2a
  or higher
• OCFS build is not currently upward compatible
  with kernel (pre SP3) ? must ensure OCFS build
  exists for each new Kernel version prior to
  upgrading kernel

24
OCFS and RAC

• Maintains cache coherency across nodes for the
  filesystem metadata only
• Does not synchronize the data cache buffers
  across nodes, lets RAC handle that
• OCFS journals filesystem metadata changes only
• Filedata changes are journalled by RAC (log
  files)
• Overcomes some limitations of raw devices on
  Linux
• No limit on number of files
• Allows for very large files (max 2TB)
• Max volume size 32G (4K block) to 8T (1M block)
• Oracle DB performance is comparable to raw
• kernel e.25 is strongly recommended for use with
  OCFS 1.0.9 (remove old kernel tuning parameters)
  

25
Install Tips for OCFS

• Ensure OCFS rpm corresponds to kernel version
• uname r (i.e. 2.4.19-4GB)
• Remember to also download rpms for OCFS Support
  Tools and Additional Tools
• Download the dd/tar/cp rpm that supports o_direct
• Use rpm Uv to install all 4 rpms on all nodes
• Use OCFS for Oracle DB files only, not Oracle
  binaries (OCFS 1.0.x was not designed as a
  general purpose filesystem).

26
Installation Flowchart for oracm and Oracle
Install 9.2.0.1 software with the RAC option
Install the oracm from the 9.2.0.3 patchset
Configure private interconnect and quorum device
Install the oracm from the 9.2.0.1 CD-ROM
Kill the oracm and watchdog process
Install the 9.2.0.3 patchset
Configure ocmargs.ora and cmcfg.ora
modify ocmargs.ora and cmcfg.ora (remove
watchdog)
Fix empty directory bug
Load the softdog and start with ./ocmstart.sh
the cluster manager on both nodes
Load the hangcheck-timer module with lsmod
Start with ./ocmstart.sh the cluster manager
27
Hangcheck NM, and CM Flow(After V9.2.0.2)
Oracle Instance
Cluster Manager (including Node Monitor)
Oracm maintains both, node status view and
instance status view.
User-mode
Kernel-mode
The hangcheck-timer monitors the kernel for
hangs, and resets the node if needed.
Hangcheck-timer
28
Post Installation

• To enable asynchronous I/O must re-link Oracle to
  use skgaioi.o
• Adjust UDP send / receive buffer size to 256K
• Larger Buffer Cache
• Create an in-memory file system on the /dev/shm
  (mount -t shm shmfs -o size8g /dev/shm)
• To enable the extended buffer cache feature, set
  the init.ora paramter USE_INDIRECT_DATA_BUFFERS
  true
• Increasing Address Space
• Default 1.7 GB of address space for its SGA.
• See Metalink Note 200266.1 for details and a
  sample program.

29
Create RAC database using DBCA

• Create Database
• Use DBCA to simplify DB creation
• Start gsd ( global services daemon ) on all
  nodes, if it is not already running.
• Set MAXINSTANCES, MAXLOGFILES, MAXLOGMEMBERS,
  MAXLOGHISTORY, MAXDATAFILES (auto with DBCA)
• Create tablespaces as locally Managed (auto with
  DBCA)
• Create all tablespaces with ASSM (auto with DBCA)
• Configure automatic UNDO management (auto with
  DBCA)
• Use SPFILE instead of multiple init.oras (auto
  with DBCA)

30
Validate RAC Configuration

• Instances running on all nodes
• SQL select from gvinstance
• RAC communicating over the private Interconnect
• SQL oradebug setmypid
• SQL oradebug ipc
• SQL oradebug tracefile_name
• /home/oracle/admin/RAC92_1/udump/rac92_1_ora_13438
  41.trc
• Check trace file in the user_dump_dest
• SSKGXPT 0x2ab25bc flags info for network
  0
• socket no 10 IP 204.152.65.33 UDP
  49197
• sflags SSKGXPT_UP
• info for network 1
• socket no 0 IP 0.0.0.0 UDP 0
• sflags SSKGXPT_DOWN
• RAC is using desired IPC protocol Check
  Alert.log
• ...
• cluster interconnect IPC versionOracle UDP/IP
• IPC Vendor 1 proto 2 Version 1.0
• PMON started with pid2

31
Configure srvconfig / srvctl

• SRVCTL uses information from srvconfig
• Reads ORACLE_HOME/srvm/config /srvConfig.loc
  information
• File can be a RAW Device or OCFS file
• Srvconfig -init
• gsd must be running
• Add ORACLE_HOME
• srvctl add database -d db_name -o oracle_home
  -m domain_name -s spfile
• Add instances (for each instance enter the
  command)
• srvctl add instance -d db_name -i sid -n node

32
Application Deployment

• Same guidelines as single instance
• SQL Tuning
• Sequence Caching
• Partition large objects
• Use different block sizes
• Tune instance recovery
• Avoid DDL
• Use LMTs and ASSM as noted earlier

33
Agenda

• Planning Best Practices
• Architecture
• Expectation setting
• Objectives and success criteria
• Project plan
• Implementation Best Practices
• Infrastructure considerations
• Installation/configuration
• Database creation
• Application considerations
• Operational Best Practices
• Backup Recovery
• Performance Monitoring and Tuning
• Production Migration

34
Operations

• Same DBA procedures as single instance, with some
  minor, mostly mechanical differences.
• Managing the Oracle environment
• Starting/stopping cluster services (ocmstart.sh)
• Starting/stopping gsd
• Managing multiple redo log threads
• Startup and shutdown of the database
• Use srvctl
• Backup and recovery
• Performance Monitoring and Tuning
• Production migration

35
Operations srvconfig / srvctl

• Use SRVCTL to administer your RAC database
  environment.
• OEM and the Oracle Intelligent Agent use the
  configuration information that SRVCTL generates
  to discover and monitor nodes in your cluster.
• Global Services Daemon (GSD) receives requests
  from SRVCTL to execute administrative job tasks,
  such as startup or shutdown.
• GSD must be started on all the nodes in your RAC
  environment so that the manageability features
  and tools operate properly. (GSDCTL)

36
Operations Backup Recovery

• RMAN is the most efficient option for Backup
  Recovery
• Managing the snapshot control file location.
• Managing the control file autobackup feature.
• Managing archived logs in RAC choose proper
  archiving scheme.
• Node Affinity Awareness
• RMAN and Oracle Net in RAC apply
• you cannot specify a net service name that uses
  Oracle Net features to distribute RMAN
  connections to more than one instance.
• Oracle Enterprise Manager
• GUI interface to Recovery Manager

37
Performance Monitoring and Tuning

• Tune first for single instance 9i
• Use Statspack
• Separate 1 GB tablespace for Statspack
• snapshots at 10-20 min intervals during stress
  testing, hourly during normal operations
• Run on all instances, staggered
• Supplement with scripts/tracing
• Monitor VSESSION_WAIT to see which blocks are
  involved in wait events
• Trace events like 10046/8 can provide additional
  wait event details
• Monitor Alert logs and trace files, as on single
  instance
• Oracle Performance Manager
• RAC-specific views
• Supplement with System-level monitoring
• CPU utilization never 100
• I/O service times never acceptable thresholds
• CPU run queues at optimal levels

38
Performance Monitoring and Tuning

• Obvious application deficiency on a single node
  cant be solved by multiple nodes.
• Single points of contention.
• Not scalable on SMP
• I/O bound on single instance DB
• Tuning on single instance DB to ensure
  applications scalable first
• Identify/tune contention using vsegment_statistic
  s to identify objects involved
• Concentrate on the top 5 Statspack timed events
  if majority of time is spent waiting
• Concentrate on bad SQL if CPU bound
• Maintain a balanced load on underlying systems
  (DB, OS, storage subsystem, etc. )
• Excessive load on individual components can
  invoke aberrant behaviour.

39
Performance Monitoring and Tuning

• Deciding if RAC is the performance bottleneck
• Amount of Cross Instance Traffic
• Type of requests
• Type of blocks
• Latency
• Block receive time
• buffer size factor
• bandwidth factor

40
Production Migration

• Adhere to strong Systems Life Cycle Disciplines
• Comprehensive test plans (functional and stress)
• Rehearsed production migration plan
• Change Control
• Separate environments for Dev, Test, QA/UAT,
  Production
• System AND application change control
• Log changes to spfile
• Backup and recovery procedures
• Security controls
• Support Procedures

41
Next Steps.

• Recommended sessions
• List 1 or 2 sessions that complement this session
• Recommended demos and/or hands-on labs
• List of or two demos or labs that will let them
  see this product in action.
• See Your Business in Our Software
• Visit the DEMOgrounds for a customized
  architectural review, see a customized demo with
  Solutions Factory, or receive a personalized
  proposal. Visit the DEMOgrounds for more
  information.
• Relevant web sites to visit for more information
• List urls here.

42
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43
(No Transcript)
44
Resources

• RedHat Linux
• http//www.redhat.com/oracle/
• Linux Center - Technical White Papers
  Documentation
• http//otn.oracle.com/tech/linux/tech_wp.html
• Tips and Techniques Install and Configure
  Oracle9i on Red Hat Linux Advanced Server by
  Deepak Patel, Oracle Corporation
• http//otn.oracle.com/tech/linux/pdf/installtips_f
  inal.pdf
• Tips and Techniques Install and Configure
  Oracle9i on SLES8 / United Linux 1.0
• http//www.suse.com/en/business/certifications/cer
  tified_software/oracle/db/9iR2_sles8.html

45
United Linux 1.0 Resources

• United Linux
• http//www.unitedlinux.com
• SuSE
• http//www.suse.com/us/business/products/server/sl
  es/index.html
• Connectiva
• http//www.connectiva.com
• SCO Group (Formerly Caldera System) -
  http//www.ebizenterprises.com/page1.asp?p463
• TurboLinux
• http//www.turbolinux.com/

46
Recommended one-off patches

• Bug 2820871 - ORA-29740 NODE EVICTION DESIGN
  ALGORITHM AND ABRUPT TIME CHANGEARU 9.2.0.3 ARU
  4161735 completed for LINUX Intel 
• Bug 2420930 - GET ORA-600 KSXPMPRP1 DURING
  STARTUP IN RAC MODE WITH LARGER BUFFERS. This
  was mysteriously included in 9.2.0.2, but not in
  9.2.0.3. Bug 2875050 was opened for this issue.
  ARU 9.2.0.3 ARU 4202164completed for LINUX
  Intel  
• Bug 2420930 - GET ORA-600 KSXPMPRP1 DURING
  STARTUP IN RAC MODE WITH LARGER BUFFERS Bug
  2922471 Fractured block found during
  crash/instance recovery. Not an Oracle bug. Do
  not use intr for the mount option.

47
Recommended one-off patches

• Bug2844009 - MISSING LIBCXA.SO.3 LIBRARY ISSUE
  IN PSR 9203. ARU 9.2.0.3 ARU 4046387 completed
  for LINUX Intel 
• Bug 2779294 node_list does not populated into
  oraInventory/ContentsXML/inventory.xml. opatch
  install will only apply to local node.
  Workaround is editing inventory.xml documented in
  bug 2742686.
•  
• Bug 2646914, 2675090, 2706220 and 2695783 -
  ORA-600 KCCSBCK_FIRST, 2 on linux and W2K
  platform after installing 9.2.0.2. Very
  important patch, missing from 9.2.0.3ARU
  9.2.0.3 ARU 4110670 completed for LINUX
  Intel        

48
Hangcheck-timer and Oracle Cluster Manager

• Download Patch 2594820 from Metalink
• rpm -ivh
• Detaching watchdogd from the Cluster Manager (Bug
  2495915)
• The removal of the watchdogd
• ORACLE_HOME/oracm/admin/cmcfg.ora
• WatchdogTimerMargin
• WatchdogSafetyMargin
• KernelModuleNamehangcheck-timer
• CMDiskFile from optional to mandatory
• CM quorum partition of cluster participation.

49
Hangcheck-timer and Oracle Cluster Manager

• remove or comment out from the /etc/rc.local
  file
• /sbin/insmod softdog nowayout0 soft_noboot1
  soft_margin60
• ADD to rc.local, execute as root to load
• /sbin/insmod hangcheck-timer.o hangcheck_tick30
  hangcheck_margin180

50
Hangcheck-timer and Oracle Cluster Manager

• inclusion of the hangcheck-timer kernel module
• Parameter Service
  Value
• ----------------- -----------------
  ---------------
• hangcheck_tick hangcheck-timer
  30 seconds
• hangcheck_margin hangcheck-timer
  180 seconds
• KernelModuleName oracm
  hangcheck-timer
• MissCount oracm
  hangcheck_tick
• 
  hangcheck_margin
• 
  ( 210 seconds)

51
Hangcheck-timer and Oracle Cluster Manager

• cmcfg.ora example
• HeartBeat15000
• ClusterNameOracle Cluster Manager, version 9i
• KernelModuleNamehangcheck-timer
• PollInterval1000
• MissCount215
• PrivateNodeNamesint-node1 int-node2
• PublicNodeNamesnode1 node2
• ServicePort9998
• CmDiskFile/ocfsdisk1/quorum/quorumfile
• HostNameint-node1

52
Hangcheck-timer and Oracle Cluster Manager

• Parameters for ocmargs.ora
• oracm
• norestart 1800

53
Linux Monitoring and Configuration Tools

• Overall tools sar, vmstat
• CPU /proc/cpuinfo, mpstat, top
• Memory /proc/meminfo, /proc/slabinfo, free
• Disk I/O iostat
• Network /proc/net/dev, netstat, mii-tool
• Kernel Version and Rel. cat /proc/version
• Types of I/O Cards lspci vv
• Kernel Modules Loaded lsmod, cat /proc/modules
• List all PCI devices (HW) lspci v
• Startup changes /etc/sysctl.conf, /etc/rc.local
• Kernel messages /var/log/messages, /var/log/dmesg
  
• OS error codes /usr/src/linux/include/asm/errno.h
  
• OS calls /usr/sbin/strace-p

54
Post Installation

• Increasing Address Space
• Default 1.7 GB of address space for its SGA.
• Shutdown all instances of Oracle
  
• cd ORACLE_HOME/lib
  
• cp -a libserver9.a libserver9.a.org
• to make a backup copy
• cd ORACLE_HOME/rdbms/lib
  
• genksms -s 0x15000000 ksms.s
• lower SGA base to 0x15000000
• make -f ins_rdbms.mk ksms.o
• compile in new SGA base address
• make -f ins_rdbms.mk ioracle (relink)

55
Post Installation

• Increasing Address Space Cont.
• sysctl w kernel.shmmax3000000000
• Lower process base
• Find out the pid of the process (shell) from
  where oracle will be started using ps (Oracle -
  echo )
• changing /proc/pid/mapped_base to 0x10000000 and
  restarting oracle
• Metalink Note 200266.1

56
Post Installation
Default
After Relink
0xFFFFFFFF
0xFFFFFFFF
Reserved for kernel
Reserved for kernel
0xC0000000
0xC0000000
Variable SGA
Variable SGA
DB Buffers (SGA)
DB Buffers (SGA)
sga_base (relink Oracle)
0x50000000
mapped_base (/proc//mapped_base)
0x40000000
Code, etc.
0x15000000
0x10000000
Code, etc.
0x00000000
0x00000000
Lowering of mapped base
57
Post Installation

• Larger Buffer Cache does buffer cache increase
  with larger SGA
• Create an in-memory file system on the /dev/shm
• mount -t shm shmfs -o size8g /dev/shm
• To enable the extended buffer cache feature, set
  the init.ora paramter
• USE_INDIRECT_DATA_BUFFERS true
• Dont Use dynamic cache parameters
• DB_CACHE_SIZE
• DB_K_CACHE_SIZE
• Limitations apply to the extended buffer cache
  feature on Linux
• You cannot change the size of the buffer cache
  while the instance is running.
• You cannot create or use tablespaces with
  non-standard block sizes.

58
Post Installation

• Adjust send / receive buffer size to 256K
• Tuning the default and maximum window sizes
• /proc/sys/net/core/rmem_default - default
  receive window
• /proc/sys/net/core/rmem_max - maximum
  receive window
• /proc/sys/net/core/wmem_default - default send
  window
• /proc/sys/net/core/wmem_max - maximum send
  window
•  
• sysctl -w net.core.rmem_max262144
• sysctl -w net.core.wmem_max262144
• sysctl -w net.core.rmem_default262144
• sysctl -w net.core.wmem_default262144

59
Post Installation

• To enable asynchronous I/O must re-link Oracle to
  use skgaioi.o
• cd to ORACLE_HOME/rdbms/lib
• make -f ins_rdbms.mk async_on
• make -f ins_rdbms.mk ioracle
• set 'disk_asynch_iotrue' (default value is true)
  
• set 'filesystemio_optionsasynch (RAW Only)