Re: OCR / VD external vs. normal redundancy using NFS.

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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