handling disks for ASM – when DB, Linux and Storage admins work together

A proper management of ASM Disks can be a complicated task.

On DOAG2015 I discussed with Martin Bach about the concept in my current company, where we implemented a setting which is consistent, robust and enables Storage, Linux and DB admins to work together easily.

As we started to think about ASM when 10.1 was out we tried to evaluate our possibility. asmlib was discarded quite early as it only increased complexity without additional (more...)

How to rename ASM disk groups in Exadata

Deployment of Exadata requires you to generate configuration using Oracle Exadata Deployment Assistant (OEDA). Within the same the default  ASM disk groups names are DBFS_DG, RECOC1 and DATAC1. I usually change those to RECO01 and DATA01 as others doesn’t make sense to me and the only place where I find the default ones is on Exadata.

I had an incident last year where the Exadata deployed half way through and names were left by default (more...)

Introducing Oracle ASM Filter Driver

The Oracle ASMFD (Filter Driver) was introduced in Oracle Database 12.1.0.2 and as of the moment it is available on Linux systems only.

Oracle ASM Filter Driver is a kernel module very much like the ASMLIB that resides in the I/O path of the Oracle ASM disks. It provides an interface between the Oracle binaries and the underlying operating environment.

Here are some of the features of ASMFD:

  • Reject non-Oracle I/O

The (more...)

PRCA-1057 : Failed to retrieve the password file location used by ASM

After the Oracle Restart (Grid Infrastructure) upgrade from 11.2. to 12.1.0.2 , you might encounter the below lines in the ASM alert log file

Tue Jun 23 01:16:01 2015
WARNING: unknown state for ASM password file location resource, Return Value: 3
WARNING: unknown state for ASM password file location resource, Return Value: 3

After the upgrade, below command can get the error

[grid@oracle1 ~]$ srvctl config asm
ASM home: <crs home=''>
 (more...)

Restoring a Database to a New Diskgroup

I had the pleasure of rebuilding an Exadata rack for a customer a while back, and it provided a pretty good refresher in backup and recovery for me.  As DBAs, we back up databases all the time, but the restores are performed much less frequently.  In the case of this rack, there were several databases across multiple ASM diskgroups.  One of the goals of the rebuild was to consolidate all of the databases into a (more...)

Oracle’s ASM Filter Driver Revisited

filter

Almost exactly a year ago I published a post covering my first impressions of the ASM Filter Driver (ASMFD) released in Oracle 12.1.0.2, followed swiftly by a second post showing that it didn’t work with 4k native devices.

When I wrote that first post I was about to start my summer holidays, so I’m afraid to admit that I was a little sloppy and made some false assumptions toward the end – assumptions (more...)

ASM not starting with ORA-00845 – how to fix ASM parameter file

Few days ago I saw great post from Norman Dunbar on how to fix a broken ASM spfile.

With version 11gR2 ASM spfile can be stored in ASM diskgroup and by default Oracle Installer will put it there. So if you want to create pfile from spfile your ASM instance should be up and running.

If you have incorrect parameter in ASM spfile which is blocking ASM to start than you have slight problem. You (more...)

Mount ASM diskgroups with new ASM instance

Imagine you have 11gR2 Oracle Restart configuration with database files located in ASM.

After server crash you realized that local disks are corrupted and with local disks you lost all Oracle installations. Even though this is important system you don’t have database backup (always take backups!).

But you managed to save all ASM disks as they were located on separate storage.


This will be small beginner guide on how to help yourself in such (more...)

No Write Permission on ACFS Mount Point



Last night, I managed to create the ACFS Mount Point after resolving the issue "ACFS-9459: ASVM/ACFS is not supported on this os version". But, after creating the ACFS Mount Point, I'm unable to create or touch any files under this ACFS Mount Point.

Though, I tried to touch a file to create files under this ACFS Mount Point using OS User Oracle and Root, it's failing with the following error:

"touch: cannot touch `x': (more...)

Using Oracle Flex ASM with single instance database

Oracle Flex ASM was introduced in 12c version. This is one of the best features introduced with new version in my opinion.

I won’t speak in detail about Flex ASM because you can find more information in documentation. In this post I will concentrate on how Flex ASM handles crash of ASM instance.

For this test I’ve created 2 node cluster - 12c Grid Infrastructure with Flex ASM enabled.


$ asmcmd showclustermode
ASM cluster : (more...)

ASM Startup Fails With ORA-04031 After Adding CPUs

A few weeks ago we upgraded one of our production server, adding another CPU tray. This brought the number of CPU cores from 80 to 160, and took us from 2Tb of RAM to 4Tb (just in time for Oracle to announce the in-memory database in 12.1.0.2!).

However when I went to start things up, ASM wasn't starting up, giving me these errors:

ORA-04031: unable to allocate 32 bytes of shared (more...)

ASM Metadata, Internals and Diagnostic Utilities

If you use ASM on a regular basis, you may find that knowledge of the internals can be very useful for advanced troubleshooting and in general to acquire familiarity with the technology. In particular this is even more relevant when using ASM capabilities for data redundancy/mirroring (i.e. when deploying disk groups with normal or high redundancy).

I have first started investigating this topic when deploying 10g RAC databases in 2005. From time to time (more...)

Oracle ASM 12c: New Features

Last week I was lucky enough to be presenting at the UKOUG AIM SIG. There was a decent enough crowd in attendance and there were some really interesting talks and some really good speakers. In particularly I found Chris Lawless speaking on replication a particularly engaging speaker, and Dave Webster really held the audiences attention late in day.

I was giving a presentation on the new features available to you with 12c ASM. The presentation (more...)

Working Around an ASM Startup Problem

Scenario

I recently hit the problem covered in MOS note “ASM Instance Is Not Coming Up ORA-00064 (1,4468736,Kfchl Array) Kfchl Array (Doc ID 1328620.1)” mid-way through a Grid Infrastructure upgrade from 11.2.0.2 BP16 to 11.2.0.4 BP3 on Exadata. Specifically, it was the application of prerequisite patch 17783101 (required for downgrades) to node 3 that hit the problem. At this point nodes 1 and 2 had been successfully patched (more...)

Bug 18223021 : DISK FILE OPERATIONS I/O ON HP-UX.

We have been dealing with a strange ASM  behavior over the past few months across all ASM instances in our multiple Oracle 11gR2 (11.2.0.2) Cluster envs on HPUX 11.31 OS. Even a simple and typical ASM task like, adding new disk to ASM disk group, disk group mount/unmount and querying for CANDIDATE asm disks was taking min of 20 minutes, and sometimes infinity time. This behavior caused a lot of performance (more...)

How to Recover Files from a Dropped ASM Disk Group

Topic: This post describes a few tips and techniques on how to recover ASM files from a dropped disk group and an example of how to 'undrop' an ASM disk group

Context: This research stems from a recent case I have investigated where the data disk group of a test (more...)

Openfiler on Virtualbox and 12c Oracle Flex ASM

Original Post can be viewed at Openfiler on Virtualbox and 12c Oracle Flex ASM

Last week Oracle released 12c database and Oracle blogosphere is bustling with lot of people posting details about new versions and setup. I too decided to take plunge and setup my own RAC cluster. I had (more...)

Physical vs Logical Blocksize on ASMLib Devices

As you all may know, ASMLib is a recommended module for Oracle databases running on Linux platforms and it is an embedded module for UEK (Oracle Unbreakable Kernel) users. Oracle announced that (two years ago or so) they will no longer maintain ASMLib for Red Hat compatible kernel but this does not mean that they abandon the project, rather it is mainly related to the effort they need to put in maintaining the module for multiple kernel versions.

A while ago, Oracle added a new feature to ASMLib allowing ASM devices to choose between physical or logical block sizes in (more...)

¿Cómo mover ocr y vdisk a nuevo disk array?

No hace mucho, uno de mis clientes inició el proceso de migración de su disk storage system, desde EMC CX4 hacia EMC VNX. Ellos tienen sus bases de datos operando con Oracle RAC 11.2.0.3, por lo que siguieron el procedimiento de agregar LUNs del nuevo EMC VNX en los diskgroups de datos, para luego retirar los LUNs del antiguo EMC CX4, aprovechando el rebalanceo automático que hace ASM al agregarle y (more...)

asmcmd non-interactive commands in MS-DOS Batches

In the last days I was fighting with a nice behaviour of the asmcmd non-interactive mode in MS-DOS batches.

I wanted to delete several files located in ASM within a MS-DOS batch:

REM Script: asm_cleanup_DB112.cmd
set ORACLE_BASE=E:\oracle
set ORACLE_HOME=E:\oracle\product\grid-11.2.0
set ORACLE_SID=+ASM
set PATH=%ORACLE_HOME%\bin;%PATH%
asmcmd rm -f +TEMP/db112/temp_01. (more...)