RE: ASM - creating diskgroup error...RESOLUTION

From: Luca Canali <Luca.Canali_at_cern.ch>
Date: Fri, 11 Jan 2008 15:36:09 +0100
Message-ID: <B18EB20A5208EB4DBE0DD2412549861C8BA1C9@cernxchg47.cern.ch>

> The bottom line is that ASM must have a minimum disk size requirement
for creating a disk group - I just don't know what it is, yet.

ASM creates and maintains a few 'hidden files'/metadata (FILE# <128) and disk headers. The largest metadata file is file#3 (active change directory) which has a size of 42MB times the number of instances you have (in RAC of course). From your logs I can see that the allocation space error was indeed on file #3
In Oracle 10g there are 6 ASM 'hidden files'. An example from a test DB of mine (where I use normal redundancy and 6 instances):

GROUP# FILE# FILESIZE_AFTER_MIRR RAW_FILE_SIZE

---------- ---------- ------------------- -------------
         1          1             2097152       6291456
         1          2             1048576       3145728
         1          3           264241152     795869184
         1          4             1392640       6291456
         1          5             1048576       3145728
         1          6             1048576       3145728

Regards,
Luca

-----Original Message-----
From: oracle-l-bounce_at_freelists.org
[mailto:oracle-l-bounce_at_freelists.org] On Behalf Of DIANNA GIBBS Sent: Friday, January 11, 2008 2:52 PM
To: DIANNA GIBBS; oracle-l_at_freelists.org Cc: chris.langston_at_aa.com
Subject: Re: ASM - creating diskgroup error...RESOLUTION

Special thanks to Romas and everyone else for replying. Here's more information if interested in the fix.

>
> I'm guessing at this point because I was unable to find minimum size
> for ASM group.
>
> ASM is very like any other LVM manager should have some sort of
> private area to keep control information. If the size of that private
> area is over 11Mb you won't be able to encapsulate 11Mb disk. It's
> very easy to find you the size of it by substracting space reported by

> ASM for one particular group from raw volume size.
>

Here more info from Chris:

We had allocated disk slices to be used for multiple instances. ASM recommends using slice 4. We had assigned certain disk for certain instances but the other DBA had used the slice 4 of the c4t2d5 disk that was suppose to be used for my flash disk group. That left only the slice 7 partitions which are all 11 MB in size which is apparently too small to use to create an ASM disk group. I haven't found documentation to state what the minimum size is suppose to be but after removing the c4t2d5s4 slice from the test disk group, we were able to successfully use it to create a new disk group by assigning that slice to it.

The bottom line is that ASM must have a minimum disk size requirement for creating a disk group - I just don't know what it is, yet.

>>> "DIANNA GIBBS" <DIANNA.GIBBS_at_childrens.com> 01/10/08 12:01 AM >>>

I have a friend trying to create an ASM diskgroup and getting errors - any idea how he needs to proceed? Thanks in advance.

Here are the details.

Trying to create a NEW diskgroup in ASM. OS: SunOS 5.8 Generic_117350-49 sun4u sparc SUNW,Sun-Fire ORACLE: SQL*Plus: Release 10.2.0.2.0

Raw Device:
lrwxrwxrwx 1 oracle dba 55 Jul 19 12:18 c4t2d5s7 -> ../../devices/ssm_at_0,0/pci_at_1a,700000/lpfc_at_2/sd_at_2,5:h,raw

ORACLE_SID = +ASM DBCA steps:

1) Configure Automatic Storage Management
2) Create New
3) Disk Group Name: QSTDEV_FLASH
4) Redunancy: External (The SAN takes care of it)
5) Select disk path: /dev/rdsk/c4t2d5s7 
         HEADER STATUS: Candidate
         ASM Name: (blank)
         Size (MB): 11

ERRORS:
 ORA-15018: diskgroup cannot be created
 ORA-15041: diskgroup space exhausted

---

ASM alert log from DBCA session:

Wed Jan 9 20:02:25 2008
SQL> CREATE DISKGROUP QSTDEV_FLASH External REDUNDANCY DISK '/dev/rdsk/c4t2d5s7' SIZE 11M
Wed Jan 9 20:02:26 2008
NOTE: initializing header on grp 12 disk QSTDEV_FLASH_0000 NOTE: PST update: grp = 12
Wed Jan 9 20:02:26 2008
NOTE: group QSTDEV_FLASH: initial PST locations: disk 0000 (PST copy 0) Wed Jan 9 20:02:26 2008

NOTE: cache registered group QSTDEV_FLASH number=12 incarn=0xd287e4d8
NOTE: cache opening disk 0 of grp 12: QSTDEV_FLASH_0000
path:/dev/rdsk/c4t2d5s7
NOTE: cache creating group 12/0xD287E4D8 (QSTDEV_FLASH)
NOTE: cache mounting group 12/0xD287E4D8 (QSTDEV_FLASH) succeeded
NOTE: allocating F1X0 on grp 12 disk QSTDEV_FLASH_0000

WARNING: allocation failure on disk QSTDEV_FLASH_0000 for file 3 xnum 7 NOTE: cache dismounting group 12/0xD287E4D8 (QSTDEV_FLASH) NOTE: erasing header on grp 12 disk QSTDEV_FLASH_0000 ERROR: diskgroup QSTDEV_FLASH was not created

---

I had just successfully create a diskgroup before I started getting this error.
I've been able to successfully add this disk to an existing diskgroup. I've been able to add other disk to other diskgroups. I CANNOT create this diskgroup, or any other diskgroup, with any disk discovered by ASM.
Same error occurs if done thru SQL*Plus.

(broken up for clarity)
asm_diskstring=

'/dev/rdsk/c4t2d6s4',
'/dev/rdsk/c4t2d13s4',
'/dev/rdsk/c4t2d19s4',
'/dev/rdsk/c4t2d12*',
'/dev/rdsk/c4t2d28s4',
'/dev/rdsk/c4t2d18s4',
'/dev/rdsk/c4t2d12s4',
'/dev/rdsk/c4t2d21s4',
'/dev/rdsk/c4t2d14s4',
'/dev/rdsk/c4t2d7s4',
'/dev/rdsk/c4t2d23s4',
'/dev/rdsk/c4t2d15s4',
'/dev/rdsk/c4t2d8s4',
'/dev/rdsk/c4t2d8s4',
'/dev/rdsk/c4t2d9*',
'/dev/rdsk/c4t2d16*',
'/dev/rdsk/c4t2d25*',
'/dev/rdsk/c4t2d10*',
'/dev/rdsk/c4t2d17*',
'/dev/rdsk/c4t2d27*',
'/dev/rdsk/c4t2d5*',

There are 12 diskgroup currently - 11 mounted, 1 dismounted.

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Received on Fri Jan 11 2008 - 08:36:09 CST