Re: OCR / VD external vs. normal redundancy using NFS.
- From: Andrew Kerber <andrew.kerber@xxxxxxxxx>
- To: david.robillard@xxxxxxxxx
- Date: Wed, 14 Jul 2010 15:33:20 -0500
I would love to see your udev script.
Keep in mind that Oracle will automatically back up your OCR to all the
cluster nodes on a regular basis so you will have that available for
recovery. I would hope that the ASM access is sufficiently restricted that
the uneducated person wont be able to accidentally delete the wrong files.
That being said, I do recall the time as a junior DBA when I deleted all the
data files from my qa database when I thought I was working in an entirely
different environment, so I have to agree having another backup to account
for user error cannot hurt..
On Wed, Jul 14, 2010 at 3:03 PM, David Robillard
<david.robillard@xxxxxxxxx>wrote:
> Hello Freek,
>
> I just finished the Grid Infrastructure reconfiguration from NFSv3 to
> ASM with iSCSI LUNs. As you proposed, I created an ASM disk group CRS
> using "normal" redundancy to store the CRS files. ASM disk groups DATA
> and FRA are using "external" redundancy and will be used for database
> files. Everything looks good.
>
> As a side note, I didn't use ASMLib because I don't like to maintain
> an extra kernel module which could cause problems after a kernel
> upgrade. Besides, ASMLib is not really needed since you can do
> everything via udev(7). If anyone is interested by my udev setup, just
> let me know. It's very easy and IMHO, it's clean.
>
> Quick question if you don't mind. Even if the OCR file is mirrored
> within the +CRS disk group, wouldn't it be a good idea to create
> another OCR disk on another disk group, say +FRA, just to prevent from
> admin/human errors?
>
> Many thanks,
>
> David
>
> On Fri, Jul 9, 2010 at 7:11 PM, D'Hooge Freek <Freek.DHooge@xxxxxxxxx>
> wrote:
> > David,
> >
> > See following oracle documentation part:
> http://download.oracle.com/docs/cd/E11882_01/install.112/e10812/storage.htm#sthref536
> >
> > When using normal redundancy, Oracle will create 3 voting disks and 1 ocr
> device, which will be mirrored.
> > When using high redundancy, Oracle will create 5 voting disks and 1 ocr
> device, which will be mirrored 2 times.
> >
> > The output below comes from a setup where I have a separate normal
> redundancy diskgroup to hold my cluster files. I needed 3 different luns in
> this diskgroup before I could create it.
> >
> > Also note that you can't see the voting disks as "files" within the
> diskgroup.
> > My guess is that Oracle uses a header within each asm disk to store the
> voting disk.
> >
> > [grid@arsvorats1 ~]$ crsctl query css votedisk
> > ## STATE File Universal Id File Name Disk group
> > -- ----- ----------------- --------- ---------
> > 1. ONLINE 7855e73b3d2a4fb3bf901beecad62093
> (/dev/oracle/asm_clfilests1p1) [DG_CLUSTER]
> > 2. ONLINE 213259f135934f27bf86b91559a44df5
> (/dev/oracle/asm_clfilests2p1) [DG_CLUSTER]
> > 3. ONLINE 1b12d9dc6d2b4fb8bfe63b365e2db555
> (/dev/oracle/asm_clfilests3p1) [DG_CLUSTER]
> > Located 3 voting disk(s).
> >
> >
> > [grid@arsvorats1 ~]$ ocrcheck
> > Status of Oracle Cluster Registry is as follows :
> > Version : 3
> > Total space (kbytes) : 262120
> > Used space (kbytes) : 2800
> > Available space (kbytes) : 259320
> > ID : 1074808153
> > Device/File Name : +DG_CLUSTER
> > Device/File integrity check succeeded
> >
> > Device/File not configured
> >
> > Device/File not configured
> >
> > Device/File not configured
> >
> > Device/File not configured
> >
> > Cluster registry integrity check succeeded
> >
> > Logical corruption check bypassed due to non-privileged user
> >
> >
> > [grid@arsvorats1 ~]$ export ORACLE_SID=+ASM1
> > [grid@arsvorats1 ~]$ asmcmd
> > ASMCMD> ls
> > DG_CLUSTER/
> > DG_DWHTS_DATA/
> > DG_FRA/
> > ASMCMD> cd DG_CLUSTER
> > ASMCMD> ls
> > arclorats/
> > ASMCMD> cd arclorats
> > ASMCMD> ls
> > ASMPARAMETERFILE/
> > OCRFILE/
> > ASMCMD> cd OCRFILE
> > ASMCMD> ls -l
> > Type Redund Striped Time Sys Name
> > OCRFILE MIRROR COARSE JUL 10 00:00:00 Y REGISTRY.255.721844181
> >
> >
> > SQL> set linesize 120
> > SQL> column full_alias_path format a70
> > SQL> column file_type format a15
> > SQL> select concat('+'||gname, sys_connect_by_path(aname, '/'))
> full_alias_path,
> > 2 system_created, alias_directory, file_type
> > 3 from ( select b.name gname, a.parent_index pindex, a.name aname,
> > 4 a.reference_index rindex , a.system_created,
> a.alias_directory,
> > 5 c.type file_type
> > 6 from v$asm_alias a, v$asm_diskgroup b, v$asm_file c
> > 7 where a.group_number = b.group_number
> > 8 and a.group_number = c.group_number(+)
> > 9 and a.file_number = c.file_number(+)
> > 10 and a.file_incarnation = c.incarnation(+)
> > 11 )
> > 12 where alias_directory = 'N'
> > 13 and system_created = 'Y'
> > 14 and file_type like 'OCR%'
> > 15 start with (mod(pindex, power(2, 24))) = 0
> > 16 and rindex in
> > 17 ( select a.reference_index
> > 18 from v$asm_alias a, v$asm_diskgroup b
> > 19 where a.group_number = b.group_number
> > 20 and (mod(a.parent_index, power(2, 24))) = 0
> > 21 )
> > 22 connect by prior rindex = pindex;
> >
> > FULL_ALIAS_PATH S
> A FILE_TYPE
> > ---------------------------------------------------------------------- -
> - ---------------
> > +DG_CLUSTER/arclorats/OCRFILE/REGISTRY.255.721844181 Y
> N OCRFILE
> >
> >
> > Freek D'Hooge
> > Uptime
> > Oracle Database Administrator
> > email: freek.dhooge@xxxxxxxxx
> > tel +32(0)3 451 23 82
> > http://www.uptime.be
> > disclaimer: www.uptime.be/disclaimer
> --
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>
>
>
--
Andrew W. Kerber
'If at first you dont succeed, dont take up skydiving.'
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