The below small C program will help us to identify if a Disk/Partition is still used by ASM, has been used by ASM or has not been used by ASM on Unix or Linux platforms. 1. First of all, we need to compile the below C code: #include <stdio.h> #include <fcntl.h> #define BLOCK_SIZE 4096 int main(int argc, char *argv[]) { char buf[BLOCK_SIZE]; char *fname; int fd; int count; if (argc != 2) { fprintf(stderr, "Exactly one argument … [Read more...] about How to Verify if a Disk/Partition is in Use by Oracle ASM, was used by Oracle ASM or is never used by Oracle ASM
ASM
Oracleasm Service Fails to Start After Upgrade to oracleasm-support-2.1.11-1 RPM Package
The Problem After upgrading oracleasm-support package, unable to start the oracleasm service which was working properly before the upgrade. Attempts to start the service result in: # service oracleasm start oracleasm is not enabled, use 'service oracleasm enable' or 'oracleasm init' The Solution This is caused by a regression in oracleasm-support-2.1.11-1 where the oracleasm configuration file /etc/sysconfig/oracleasm is not marked as a configuration file in the RPM spec file and is … [Read more...] about Oracleasm Service Fails to Start After Upgrade to oracleasm-support-2.1.11-1 RPM Package
Oracle ASM 12c – New Features with examples
This post discusses a few 12C ASM new features with examples: Failgroup_repair_time Online disk replace Estimate Work V$ASM_OPERATION view 1. FAILGROUP_REPAIR_TIME For earlier ASM versions, we had disk_repair_time, from 12C onwards we have failgroup_repair_time at the ASM level. Because failure group outages are more likely to be transient in nature and because replacing all the disks in a failure group is a much more expensive operation than replacing a single disk, it would … [Read more...] about Oracle ASM 12c – New Features with examples
Interview Questions : Oracle Flex ASM 12c
What is Oracle Flex ASM? Oracle Flex ASM is an ASM instance which will be running in the cluster based on cardinality defined. The default cardinality is three, but you can change it using srvctl modify asm command. It means that ASM is not required to run on each node in the cluster. In the previous release, ASM will be running on each node in the cluster and ASM clients (Database, ACFS, ADVM) can only access ASM by using an ASM on the same host. With Oracle Flex ASM, the clients can … [Read more...] about Interview Questions : Oracle Flex ASM 12c
Oracle sql script to report the list of files stored in ASM and CURRENTLY NOT OPENED
Purpose One of the features of ASM is databases consolidation. A single diskgroup will be the repository for multiple databases. The result, having a large number of datafiles. If the files were created using OMF (Oracle Managed Files) format, when the datafile is deleted on the database side, it is also deleted on the ASM side. There may be situations when the datafiles are not deleted on the ASM side, particularly when not using OMF format. With large diskgroups holding large number of … [Read more...] about Oracle sql script to report the list of files stored in ASM and CURRENTLY NOT OPENED
How to move ASM spfile from External Redundancy To Normal Redundancy in version 12.1.0.2 and above
The Ask While Installing the 12c Grid Infrastructure (GI) with the intention of having 3 copies of voting disks and OCR files, we created +GRID diskgroup with 3 underlying luns. However, because we chose "external redundancy" for the diskgroup ended up having just one copy of voting disk and OCR files with no option of multiplexing them in the same group. The Solution Before we get into the solution to this ask, lets first see what exactly is "external", "normal" and "high" … [Read more...] about How to move ASM spfile from External Redundancy To Normal Redundancy in version 12.1.0.2 and above
Manage ASM Audit Files with syslog – configure lograte and auditing
The audit file destination directories for an ASM instance can grow to contain a very large number of files if they are not regularly maintained. Having a very large number of files can cause the file system to run out of free disk space or inodes, or can cause Oracle to run very slowly due to file system directory scaling limits, which can have the appearance that the ASM instance is hanging on startup. This post explains how to use the Linux syslog facility to manage ASM auditing records so … [Read more...] about Manage ASM Audit Files with syslog – configure lograte and auditing
How to Delete ASM Disk on Multipath Device in CentOS/RHEL
The post outlines steps to remove ASM disk on multipath device (Labeled as ASMDISK01 as an example in this post) from CentOS/RHEL server. 1. First make sure that ASM disk is no longer used by any disk group, otherwise, you might risk data integrity. The DBA can check this by using asmcmd or by logging into the ASM database. 2. Find out ASM disk mapping: # oracleasm listdisks ASMDISK01 ... # oracleasm querydisk -p ASMDISK01 Disk "ASMDISK01" is a valid ASM disk /dev/sdf: … [Read more...] about How to Delete ASM Disk on Multipath Device in CentOS/RHEL
How to set custom device names using udev in CentOS/RHEL 7
There could be a requirement from client to have custom device names such as /dev/asmdisk01 for an actual device with name /dev/sdb. Follow the steps outlined in this post to set custom device names using udev. In order to create customer name (/dev/asmdisk01p1) for /dev/sdb set udev rules as below: 1. Find UUID of device First, find the the UUID of the device with the scsi_id command as shown below. # /usr/lib/udev/scsi_id -g -u /dev/sdb 1IET_00020002 Save this UUID, as this ID … [Read more...] about How to set custom device names using udev in CentOS/RHEL 7
How to set udev rule for setting the disk permission on ASM disks when using multipath on CentOS/RHEL 6
This note explains how to set udev rule for setting the disk permission on ASM disks in multipath on CentOS/RHEL 6.x. Follow the below steps if you are using multipath and want to set udev rule on multipath device. 1. Determine partitioned alias for target device # dmsetup ls |grep p1 datap1 (253, 4) ### you would see something similar to this 2. Edit /etc/udev/rules.d/12-dm-permissions.rules file to set the above device ownership as oracle:dba. # vi … [Read more...] about How to set udev rule for setting the disk permission on ASM disks when using multipath on CentOS/RHEL 6