What is os-prober The os-prober package detects all operating systems available on the machine and returns the results in a generic machine-readable format. Sometimes os-prober may cause problems when probing some special disks (Ex: Oracle ASM disks). This post describes how to disable os-prober. Disabling os-prober os-prober is invoked by the command grub2-mkconfig when generating a new GRUB configuration file. Running grub update on a busy Oracle ASM LUNS with OS probe results in timeouts … [Read more...] about How to Disable os-prober in CentOS/RHEL 7
ASM
How to check and repair ACFS with FSCK
The Problem You noticed many inconsistencies in different asm metadata views, asmcmd and os outputs that are associated with the ACFS file system. Database shows corruption in RMAN or from dbverify. Database uses ACFS. ALTER DISKGROUP CHECK REPAIR comes back clean but you still see errors or check for corruption returns back positive, eg: $ /sbin/acfsutil info fs -o iscorrupt [MOUNT_POINT] acfsutil info fs: ACFS-03037: not an ACFS file system $ /sbin/acfsutil info fs -o iscorrupt … [Read more...] about How to check and repair ACFS with FSCK
How to split BCV and open oracle ASM database
BCV (Business Continuance Volume ) is the target volume for EMC Symmetrix TimeFinder/Mirror process. When a BCV is fully synchronized with a data device, the BCV is separated or split, thus becomes available to a host for backup or other host processes. In short, a BCV split is a device to be a clone of another device. Before you use BCV split as oracle backup, you need to narrow down what is contained on the backed up volumes. You can use BCV split to backup only asm disks together with rdbms … [Read more...] about How to split BCV and open oracle ASM database
Unable to instantiate disk “ASM_DISK” – error on running ‘oracleasm scandisks’ command
The Problem The new disk has been assigned to a host and the user needs to run a scandisk. But the command fails to instantiate new disks with the below error. # oracleasm scandisks Reloading disk partitions: done Cleaning any stale ASM disks... Scanning system for ASM disks... Instantiating disk "ASM_DISK_01" Unable to instantiate disk "ASM_DISK_01" Instantiating disk "ASM_DISK_02" Unable to instantiate disk "ASM_DISK_02" Instantiating disk "ASM_DISK_03" Unable to instantiate disk … [Read more...] about Unable to instantiate disk “ASM_DISK” – error on running ‘oracleasm scandisks’ command
Understanding Device Persistence and Oracle ASMLib
Basics This post describes some advantages the Linux specific ASM library provided by Oracle (herein "ASMLib") brings to the administration of a Linux system running Oracle. Linux often presents the challenge of disk name persistence. Change the storage configuration and a disk that appeared as /dev/sdg yesterday can appear as /dev/sdh after a reboot today. How can these changes be isolated so that they do not affect ASM? Why Not Let ASM Scan All Disks? ASM scans all disks it is allowed to … [Read more...] about Understanding Device Persistence and Oracle ASMLib
ASMLib-Managed Disks on Multipathed iSCSI Targets are not Discovered after Server Reboot in CentOS/RHEL 7
The Problem Oracle Real Application Clusters (RAC) servers run on CentOS/RHEL 7 and utilizing ASMLib-managed iSCSI multipathed disks. Upon server reboot, Oracle ASMLib disks are not automatically discovered at boot time causing Oracle Cluster Ready Services (CRS) to fail to start. ASM disks are, however, correctly discovered when manually running the oracleasm scandisks command soon after the server reboot. Following is the oracleasm configuration # cat … [Read more...] about ASMLib-Managed Disks on Multipathed iSCSI Targets are not Discovered after Server Reboot in CentOS/RHEL 7
How to load SELinux Module For Oracleasm
Question: How to load the SELinux module for oracleasm? When searching for the selinux oracleasm module with the locate command it may return as if the file exists: # locate /oracleasm.pp /etc/selinux/targeted/modules/active/modules/oracleasm.pp However, when running the command semodule to load the oracleasm.pp module it fails: # semodule --verbose -i /etc/selinux/targeted/modules/active/modules/oracleasm.pp Attempting to install module … [Read more...] about How to load SELinux Module For Oracleasm
How to extend ASM disk from OS level in CentOS/RHEL
Question: How to expand the physical raw disk which is part of ASM diskgroup? Below are the steps to extend the physical disk which is part of ASM diskgroup. 1. First, you have to unmount the disk you want to extend at the ASM level. 2. Check the disks present at the OS level and their size. # lsblk NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT sda 8:0 0 12G 0 disk ├─sda1 8:1 0 500M 0 part /boot └─sda2 8:2 0 11.5G 0 part ├─ol-root 251:0 0 10.3G 0 lvm / └─ol-swap 251:1 0 1.2G 0 lvm … [Read more...] about How to extend ASM disk from OS level in CentOS/RHEL
Beginners Guide to Automatic Storage Management (ASM)
The Basics Automatic Storage Management (ASM) provides vertical integration of the file system and the volume manager for Oracle database files. ASM can provide management for single symmetric multiprocessing (SMP) machines or across multiple nodes of a cluster for Oracle Real Application Clusters (RAC) support. Oracle ASM Cluster File System (ACFS) is a multi-platform, scalable file system, and storage management technology that extends ASM functionality to support application files outside … [Read more...] about Beginners Guide to Automatic Storage Management (ASM)
Beginners Guide to Working with spfile in Oracle ASM
Introduction Starting with ASM version 11.2, the ASM spfile can be stored in an ASM disk group. Indeed, during a new ASM installation, the Oracle Universal Installer (OUI) will place the ASM spfile in the disk group that gets created during the installation. This is true for both Oracle Restart (single instance environments) and Cluster installations. It should be noted that the first disk group created during the installation is the default spfile location, but not a requirement. The spfile … [Read more...] about Beginners Guide to Working with spfile in Oracle ASM