The Geek Diary

Archives for February 2018

New Background Processes In Oracle Database 12c

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The post provides information on new background processes introduced in 12c. Background Process Description BWnn Database Writer Processes FENC Fence Monitor Process IPC0 IPC Service Background Process LDDn Global Enqueue Service Daemon Helper Slave LGnn Log Writer Worker LREG Listener Registration Process OFSD Oracle File Server Background Process RPOP Instant Recovery Repopulation Daemon SAnn SGA […]

Oracle Automatic Storage Management (ASM) concepts

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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 […]

Firewalld Command line Reference (Cheat Sheet)

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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 […]

Understanding Oracle Database Automatic SGA Memory Tuning

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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 […]

New Background Processes In Oracle Database 10g

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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 […]

ASM background processes in 11gR2

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Here is a short note on ASM background processes and their purpose in managing Oracle ASM instances. Background Process Description ASMB ASM Background Process RBAL ASM Rebalance Master Process ARBn ASM Rebalance Process DBWR Database Writer Process SMON System Monitor Process CKPT Checkpoint Process PSP0 Process Spawner Process GMON ASM Disk Group Monitor Process MARK […]

Understanding Oracle Background Processes

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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 […]

How to restore files under user’s home directory to default in Linux

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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: […]

Understanding iscsiadm Utility in CentOS / RHEL

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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 […]