The post provides information on new background processes introduced in 12c. Background ProcessDescription BWnnDatabase Writer Processes FENCFence Monitor Process IPC0IPC Service Background Process LDDnGlobal Enqueue Service Daemon Helper Slave LGnnLog Writer Worker LREGListener Registration Process OFSDOracle File Server Background Process RPOPInstant Recovery Repopulation Daemon SAnnSGA Allocator SCRBASM Disk Scrubbing Master Process SCRnASM Disk Scrubbing Slave … [Read more...] about New Background Processes In Oracle Database 12c
Archives for February 2018
Oracle Automatic Storage Management (ASM) concepts
The post provides a quick overview of Oracle Automatic Storage Management (ASM) concepts and operations. ASM Basics - ASM exists to manage file storage for the RDBMS. - ASM does NOT perform I/O on behalf of the RDBMS. I/O is performed by the RDBMS processes as it does with other storage types. Thus, ASM is not an intermediary for I/O (would be a bottleneck). - I/O can occur synchronously or asynchronously depending on the value of the DISK_ASYNCH_IO parameter. - Disks are RAW devices to … [Read more...] about Oracle Automatic Storage Management (ASM) concepts
Firewalld Command line Reference (Cheat Sheet)
firewalld is the default method in Red Hat Enterprise Linux 7 for managing host-level firewalls. Started from the firewalld. service systemd service, firewalld manages the Linux kernel netfilter subsystem using the low-level iptables, ip6tables, and ebtables commands. Default Configuration of firewalld Zones Zone name Default configuration trusted Allow all incoming traffic. home Reject incoming traffic unless related to outgoing traffic or matching the ssh, mdns, ipp-client, … [Read more...] about Firewalld Command line Reference (Cheat Sheet)
Understanding Oracle Database Automatic SGA Memory Tuning
In Oracle Database 10g, Automatic Shared Memory Management (ASMM) feature is introduced to automatically determine the size of Database buffer cache (default pool), Shared Pool, Large pool and Java pool (starting with 10gR2, the streams pool is included) by setting the parameter SGA_TARGET. This feature reduces the tasks like dynamically analyzing the database workload and redistribute memory across the SGA pools. Benefits of Automatic Shared Memory Management Automatic Shared Memory … [Read more...] about Understanding Oracle Database Automatic SGA Memory Tuning
New Background Processes In Oracle Database 10g
The background processes of the Oracle instance manage memory structures, asynchronously perform I/O to write data to a file on a disk, and perform general maintenance tasks. Each background process has a separate task but works with the other processes as well. The post provides information on some new and some pre-existing background processes in 10G which may be unfamiliar. Background ProcessDescription MMANMemory Manager RVWRRecovery Writer CTWRChange Tracking Writer … [Read more...] about New Background Processes In Oracle Database 10g
ASM background processes in 11gR2
Here is a short note on ASM background processes and their purpose in managing Oracle ASM instances. Background ProcessDescription ASMBASM Background Process RBALASM Rebalance Master Process ARBnASM Rebalance Process DBWRDatabase Writer Process SMONSystem Monitor Process CKPTCheckpoint Process PSP0Process Spawner Process GMONASM Disk Group Monitor Process MARKMark AU for Resynchronization Coordinator Process VKTMVirtual Keeper of Time Process LGWRLog Writer Process … [Read more...] about ASM background processes in 11gR2
Understanding Oracle Background Processes
Oracle Background Processes The background processes of the Oracle instance manage memory structures, asynchronously perform I/O to write data to a file on a disk, and perform general maintenance tasks. An Oracle database system consists of an Oracle database and an Oracle instance. The database consists of a set of disk files that store user data and metadata, while the Oracle/database instance contains the set of Oracle Database background processes that operate on the stored data and the … [Read more...] about Understanding Oracle Background Processes
How to restore files under user’s home directory to default in Linux
The Problem If accidentally the context or file permission of files under user's home directory had been changed, permission errors or unexpected application behavior might be encountered after this user login system. For instance, if the file permission of /home/user1/.bash_profile is wrong, login user1 will get prompt "/home/user1/.bash_profile: Permission denied": login as: user1 user1@geeklab's password: Last login: Mon Dec 15 15:08:20 2014 from geeklab2.example.com -bash: … [Read more...] about How to restore files under user’s home directory to default in Linux
Understanding iscsiadm Utility in CentOS / RHEL
Internet Small Computer System Interface (iSCSI) is an IP-based standard for connecting storage devices. iSCSI uses IP networks to encapsulate SCSI commands, allowing data to be transferred over long distances. iSCSI provides shared storage among a number of client systems. Storage devices are attached to servers (targets). Client systems (initiators) access the remote storage devices over IP networks. To the client systems, the storage devices appear to be locally attached. iSCSI uses the … [Read more...] about Understanding iscsiadm Utility in CentOS / RHEL
How to change the SCAN IP address (SCAN VIP resources) in 11gR2 Grid (CRS) environment
The IP addresses associated with the SCAN VIP resources are initially set when the SCAN resources are created. Any changes to the DNS entry for the SCAN are not automatically propagated to the clusterware and need to be done manually. This applies only to installations that are not using GNS. The information in this note can also be helpful in cases where SCAN was originally configured with just one address and is now being expanded to accommodate three IP addresses. Below is an example using … [Read more...] about How to change the SCAN IP address (SCAN VIP resources) in 11gR2 Grid (CRS) environment