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Oracle Documentation

Oracle Linux and Unbreakable Enterprise Kernel (UEK) Releases

Certification Information for Oracle Database on Linux x86-64 (Doc ID 1304727.2)

Release Schedule of Current Database Releases (Doc ID 742060.1)

Diagnostic Tools Catalog (Doc ID 559339.1)

Autonomous Health Framework (AHF) – Including TFA and ORAchk/EXAChk (Doc ID 2550798.1)

Catalog: Oracle Toolbox: Diagnostic and Analyzer Scripts – Data Collectors – Health Checks – Tools – Utilities – SRDC – All Products – Database – Exadata – EBS – JDE – Fusion – Middleware – Siebel – Sun – Peoplesoft (Doc ID 1987483.2)

Autonomous Health Checks and Diagnostics

Maximum Availability Architecture Best Practices

Oracle MAA Reference Architectures

Certified Virtualization and Partitioning Technologies for Oracle Database and RAC Product Releases

RAC Technologies Matrix for Linux Platforms

Oracle Linux Virtualization Manager

Oracle Developer Community

Managing Oracle Cluster Registry and Voting Files – Oracle 19c

Enabling Advanced Features of Oracle Net Services – Oracle 19c

Oracle Clusterware Control (CRSCTL) Utility Reference 19c


Introduction to Oracle Clusterware – Oracle Clusterware supports up to 100 nodes in a cluster on configurations running Oracle Database 10g release 2 (10.2) and later releases.

Oracle RAC

Archive for the ‘STONITH’ Category – Kevin Closson

RAC: Frequently Asked Questions (RAC FAQ) (Doc ID 220970.1)

Avoiding Split Brain

Rebootless node fencing in Oracle RAC


Understanding Linux SCSI Reservation

What are SCSI Reservations and SCSI Persistent Reservations?

How to verify that the disk is iscsi3 persistent compliant

Multicast Requirements for Networks Used by Oracle Grid Infrastructure

Grid Infrastructure Redundant Interconnect and ora.cluster_interconnect.haip (Doc ID 1210883.1)

Grid Infrastructure Startup During Patching, Install or Upgrade May Fail Due to Multicasting Requirement (Doc ID 1212703.1)

How to Validate Network and Name Resolution Setup for the Clusterware and RAC (Doc ID 1054902.1)

The Basics of IPv4 Subnet and Oracle Clusterware (Doc ID 1386709.1)

Oracle Clusterware and RAC Support for RDS Over Infiniband (Doc ID 751343.1)

Grid infrastructure (GI):HAIP on RDS is not supported (Doc ID 2328941.1)

Known Issues: Grid Infrastructure Redundant Interconnect and ora.cluster_interconnect.haip (Doc ID 1640865.1)

Oracle RAC on Third-Party Clouds

Oracle RAC on Third-Party Clouds

Self-managed Oracle RAC on Amazon EC2

Oracle RAC on Amazon EC2

FlashGrid Enables Oracle RAC in AWS


Network multicast support on Azure

How to enable broadcast and multicast support on Amazon (AWS) EC2


Alejandro Vargas – Useful Scripts

Oracle AWR Reports: Understanding I/O Statistics

How to identify IOPS in AWR reports

How to get IOPS from AWR and Real-time

Oracle Database Load Testing Tools – Overview


ASM Inherently Performs Asynchronous I/O Regardless of filesystemio_options Parameter (Doc ID 751463.1)

How To Check if Asynchronous I/O is Working On Linux (Doc ID 237299.1)

Asynchonous I/O not reported in /proc/slabinfo KIOCB slabdata (Doc ID 413389.1)

Information Center: ASMLib (Doc ID 1624409.2)

How to Configure LUNs for ASM Disks using WWID, DM-Multipathing, and ASMLIB on RHEL 5/OL 5 and RHEL 6/OL 6 and RHEL7 (Doc ID 1365511.1)

ASMLib for RHEL6

Doing synchronous IO on ASM

ASMLIB Performance vs Udev

Why use Oracle ASM for Oracle databases

Performance and Scalability Considerations for ASM Disk Groups – 12.2

Altering Disk Groups – ASM Rebalance Oracle 19c

Choosing the Right ASM Allocation Unit for a Virtualized Oracle Database

Oracle ASM and Thin Provisioning – How To Reclaim Space

Dell Deployment Best Practices for Oracle Databases with Dell EMC PowerMax – Appendix II. Oracle ASM online storage reclamation

Grid Infrastructure Installation and Upgrade Guide for Linux – Do not specify multiple partitions on a single physical disk as a disk group device

Oracle ASM Mirroring and Disk Group Redundancy

Oracle’s ASM Filter Driver Revisited]

Oracle 4k Support

Advanced Format: 4k Sector Size

Deep Dive: Oracle with 4k Sectors

Oracle Fixes The 4k SPFILE Problem…But It’s Still Broken

Using 4k Redo Logs on Flash, 4k-Disk and SSD-based Storage (Doc ID 1681266.1)

Redo log block size on all flash

Supporting 4K Sector Disks (Doc ID 1133713.1)

Supporting ASM on 4K/4096 Sector Size (SECTOR_SIZE) Disks (Doc ID 1630790.1)

Alert: After SAN Firmware Upgrade, ASM Diskgroups ( Using ASMLIB) Cannot Be Mounted Due To ORA-15085: ASM disk “” has inconsistent sector size. (Doc ID 1500460.1)

Oracle Linux 6 – ASM Instances Fail with 4K Sector Size LUN (Doc ID 2211975.1)

FAQ: Flash Storage with ASM (Doc ID 1626228.1)

19c ASM Disk Group SECTOR_SIZE


19c Specifying the Logical and Physical Sector Size

Oracle IO

Oracle I/O latency monitoring

Simple Way to Calculate OS CPU Utilization From Oracle Database V$ Views

Physical IO on Linux/

How To Change The Priority Of Oracle Database Background Processes

Throttling IO with Linux/


Oracle Redo Log

A look into oracle redo, part 7: adaptive log file sync – Frits

Adaptive Log File Sync: Oracle, Please Don’t Do That Again

LGWR I/O is Simple, But Not LGWR Processing – Kevin Closson

Tuning Redo Log Buffer

Tuning ‘log file sync’ wait events – Riyaj

Changing The Number Of Oracle Database 12c Log Writers

Log File Sync Issue (Part 3)

Warning: log write elapsed time 


Troubleshooting: ‘Log file sync’ Waits (Doc ID 1376916.1)

Adaptive Switching Between Log Write Methods can Cause ‘log file sync’ Waits (Doc ID 1462942.1)

IF: High CPU Consumption by Oracle Background Processes (Doc ID 2070348.1)

Bug 25178179 – Several sessions wait on ‘log file sync’ in a RAC environment (Doc ID 25178179.8)

Bug 27143321 – LGWR May Not Switch Back to post/wait Mode (Doc ID 27143321.8)

“Warning: log write time” Messages Seen in LGWR Trace Files (Doc ID 601316.1)

Script to Collect Log File Sync Diagnostic Information (lfsdiag.sql) (Doc ID 1064487.1)

Long Wait on Log File Sync Wait Event with Message ‘Log file sync switching to polling’ and ‘Warning: log write elapsed time’ (Doc ID 2372105.1)

Where does the log writer spend its time on?

Oracle Log File Sync Wait Event

Ouch! Log File Switch Checkpoint Incomplete

Obtaining Information about Oracle Redo Log Files

Tuning Redo Log Buffer

Oracle Log File Switch Completion

RAC Wait Event: gcs log flush sync

Oracle 11g AMM: MEMORY_TARGET, MEMORY_MAX_TARGET and /dev/shm/

Shared Memory Virtual Filesystem

How much memory is truly used by my Oracle instance?/

Oracle and NUMA

processor_group_name and SGA distribution across NUMA nodes

Numa/interleave memory/oracle

The Oracle database, in-memory parallel execution and NUMA

Oracle x$ / v$ tables

x$tables – adp-gmbh.com

DB Statistics to SGA Variable Mapping

Oracle Compression

Oracle Database compression or Storage (All Flash) compression: A performance comparison

Interested in Oracle Database Compression Best Practices and Insights?

When to Use the Various Types of Oracle Data Compression

Oracle Advanced Compression Compared to Storage-Based Compression – The Important Differences

Oracle Backup & Snapshots

Supported Backup, Restore and Recovery Operations using Third Party Snapshot Technologies (Doc ID 604683.1)

Linux CPU Performance

Linux Load Averages: Solving the Mystery

Understand Linux Load Averages and Monitor Performance of Linux

Examining Load Average

USE Method: Linux Performance Checklist

The USE Method

Understanding CPU Steal Time – when should you be worried?

Steal Time Accounting


Linux IO Performance

Little’s Law- An insight on the relation between latency and throughput

Deadline scheduler

Noop scheduler

Using the Deadline IO Scheduler

Understanding the Deadline IO Scheduler

How to use the Noop IO Scheduler

Choosing an I/O Scheduler for 4 and the 2.6 Kernel

Improving Linux System Performance with I/O Scheduler Tuning

Queue sysfs files

Increasing the maximum I/O size in Linux

SC Storage Customer Notification: Linux Large IO Sizes Can Affect iSCSI Volume Availability

What is the suggested I/O scheduler to improve disk performance when using Red Hat Enterprise Linux with virtualization?

RHEL Configuring Tuning Profiles for Storage Performance

What is the kernel parameters related to maximum size of physical I/O requests?

I/O Limits: block sizes, alignment and I/O hints

[Engineering Notes] I/O Limits: block sizes, alignment and I/O hints

Default Maximum IO Size Change in Linux Kernel

How do I disable the irqbalance service in Red Hat Enterprise Linux?

Performance Tuning Guide Red Hat Enterprise Linux 7

RHEL 7 and Oracle 12c (Single Instance and RAC)

Pure Storage – Linux Recommended Settings

Linux IO Benchmarking

Inspecting disk IO performance with fio

Getting Started With Fio



How to measure disk performance with fio and IOPing

dd — Linux manual page

fio(1) – Linux man page

ioping – Linux Man Pages


Writing udev rules


3D XPoint Memory

Linux Man Page


NTP Server – Stratum Levels Explained

Stratum Levels & NTP Explained | Welcome to the ‘Stratumopshere’

Persistent Memory

NVME nvme-get-feature

NVDIMM and the Linux Kernel

Configuring and Using Persistent Memory in RHEL 7.3

Persistent Memory Programming

Direct Access for files (DAX)

LIBNVDIMM: Non-Volatile Devices

Persistent Memory Wiki




mmap and DMA

An NVDIMM Primer (Part 1 of 2)



Using Persistent Memory Devices with the Linux Device Mapper

Chapter 28. Persistent Memory: NVDIMMs

NVDIMM Enabling in SUSE Linux Enterprise 12, Service Pack 2

Persistent Memory  – Important

How to Emulate Persistent Memory Using Dynamic Random-access Memory (DRAM)

Speeding Up I/O Workloads with Intel Optane Persistent Memory Modules – Eduardo Berrocal

Oracle 21c – Using Persistent Memory Database

File Systems and Devices on Persistent Memory (PMEM) in Database Servers May Cause Database Corruption (Doc ID 2608116.1)

Intel – Operating System Support for Persistent Memory

Persistent Memory FAQ

Intel PMDK Introduction

Linux Memory mapping


RAID 10 Vs RAID 01 (RAID 1+0 Vs RAID 0+1)

What are RAID 1, RAID 1+0 and RAID 0+1

What are SCSI Reservations and SCSI Persistent Reservations?

Virtual Storage Appliances









Shall I use Zones or LDOMs?

Oracle Solaris Containers


Assigning the appropriate processor entitled capacity

AIX for System Administrators – Physical – Virtual – Logical CPUs

Understanding CPU on AIX Power SMT Systems

Processor utilization difference between IBM AIX and Linux on Power – apple to apple comparison

Understanding CPU utilization on AIX

How to Use rPerfs for Workload Migration and Server Consolidation

Sockets, Cores, Virtual CPU, Logical CPU, Hyper-Threading: What is a CPU nowadays? – Oracle AWR AIX










Dell EMC Workload Profile Assessment for Oracle AWR Report / StatsPack Gathering Procedures Instructions



NetApp From the Ground Up – A Beginner’s Guide – Index

Netapp Blog




Pure Storage

Oracle on Pure Storage/


What’s new in ESXi 6.5 Storage Part I: UNMAP

In-Guest UNMAP Fix in ESXi 6.5 Part II: Linux

What’s New in Core Storage in vSphere 6.7 Part II: Sector Size and VMFS-6

What’s New in Core Storage in vSphere 6.7 Part V: Rate Control for Automatic VMFS UNMAP

Reclaiming Unused Space in an Oracle Database



Oracle Bloggers