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

Yes I think my next step would be to just fdisk one of the drives - basically the header.

I am not getting any real answer from Oracle though.  

On Aug 27, 2014, at 10:52 PM, Chitale, Hemant K <Hemant-K.Chitale_at_sc.com> wrote:

> 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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