RE: Trying to Simulate a disk failure for one of the disks used by ASM disk group

From: Chitale, Hemant K <Hemant-K.Chitale_at_sc.com>
Date: Thu, 28 Aug 2014 13:52:47 +0800
Message-ID: <0BDF2A25A09ADD40908745EEFC0A0FB60239B123_at_HKMGAXMB103A.zone1.scb.net>

I would use "dd" to overwrite a disk (or just the header of it) to simulate a failure.  

Was your second test also about removing a disk physically ? And the DG didn't dismount merely because permissions on the dev had been changed ?

OR was the second test different in some other way ?  

Hemant K Chitale    

From: oracle-l-bounce_at_freelists.org
[mailto:oracle-l-bounce_at_freelists.org] On Behalf Of Hanan Hit Sent: Thursday, August 28, 2014 7:16 AM
To: Oracle L
Cc: Hit Hanan Gmail
Subject: Trying to Simulate a disk failure for one of the disks used by ASM disk group  

Hi All,  

I am sorry for the large distribution but I am somehow hitting a wall.  

I have a new 12c single instance install (Oracle Database 12c Enterprise Edition Release 12.1.0.2.0 - 64bit Production) using ASM on RHEL 6.5.    

The underline storage array that I am using is MD-1220 from HP.  

I have total of 24 drives that each presented as a single drives.  

Using ASMlib.    

I was able to create the ASM instance using two disk groups (DATADG with 16 drives and FRADG with 8 disks). I am using Normal Redundancy.  

All drives were labeled (first 1M).    

Here are the compatibility details of both disk groups:  

GROUP_NUMBER NAME

• ------------------------------

COMPATIBILITY

---

DATABASE_COMPATIBILITY

---

                  2 FRADG

12.1.0.0.0

12.1.0.0.0  

                  1 DATADG

12.1.0.0.0

12.1.0.0.0    

I also modified the disk repair time for the given disk to 6 hours from the default of 3.6 hours .      

SQL> show parameter disk_  

NAME                                                         TYPE  VALUE



------------------------------------ -----------

------------------------------


asm_diskgroups                                          string  FRADG,

DATADG

asm_diskstring                                            string  ORCL:*

 

 

Now I am trying to simulate a failure of one disk (that of course shouldn't fail the DATADG).  

In the first test we physically plug out one drive (found the right device) and the DATADG was dismounted (to my surprise). This obviously didn't work as I expected. I don't think it's a fat finger issue.  

In the second test after opening a SR with Oracle, I modified the permission for the device during the run, rescan the drives but all is functioning well and not failed disk were encountered.  

# chmod 000 /dev/sdd1  

# /etc/init.d/oracleasm scandisks

Scanning the system for Oracle ASMLib disks: [ OK ]    

So finally, is there a better way to logically simulate a disk failure with Normal Redundancy and while using my infrastructure?  

Any help would be highly appreciated.  

Best,

            Hanan        

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http://www.freelists.org/webpage/oracle-l Received on Thu Aug 28 2014 - 07:52:47 CEST