RE: fdisk against the existing datagroup DISK

From: D'Hooge Freek <>
Date: Tue, 12 Apr 2011 01:27:46 +0200
Message-ID: <>


Is the asm diskgroup using external redundancy or is it mirrored? In the second case, you can relax as all the data is also on another disk. Just drop the asm disk from the diskgroup and rebuild it.

In the first case, you can check the amount of free space in the asm diskgroup. If enough space is still available (more than the lun size of an asm disk), then you can instruct asm to remove the disk from the diskgroup. Asm will then rebalance the disks to move all data from disk6 to the other disks. If you are lucky no errors will occur and afterwards you can partition the disk again and add it to the asm diskgroup. If not enough free space is available, the you need to add a new lun first (maybe you can use the /dev/sdai disk for this). I would certainly make sure that you don't reboot the server (The redhad documentation side contains a manual of how to online add/remove luns).

Anyway, make sure you have recent backups of the databases and the archived redo logs and call Oracle when you don't hear from support fast enough. Also, open a ticket with Redhat support. They should be able to tell you what is happening with the partition table of the lun, which would give you more information of how it will impact applications reading from this disk.


Freek D'Hooge
Oracle Database Administrator
tel +32(0)3 451 23 82

From: [] On Behalf Of Masha Gurenich
Sent: maandag 11 april 2011 22:56
To: Oracle L
Subject: fdisk against the existing datagroup DISK

Hi all, 

Please, help: the fdisk partition was put inside another partition.
/dev/sda was already partitioned with a single partition as /dev/sda1
/dev/sda1 was labeled as DISK6 and was part of the DATA diskgroup.
But fdisk was run against /dev/sda1 and created another partition table inside /dev/sda1.
We now have a /dev/sda1p1

That's what i did: 

[root_at_oscdevdb1 ~]# fdisk /dev/sda1
Device contains neither a valid DOS partition table, nor Sun, SGI or OSF disklabel Building a new DOS disklabel. Changes will remain in memory only, until you decide to write them. After that, of course, the previous content won't be recoverable. The number of cylinders for this disk is set to 51199. There is nothing wrong with that, but this is larger than 1024, and could in certain setups cause problems with: 1) software that runs at boot time (e.g., old versions of LILO) 2) booting and partitioning software from other OSs (e.g., DOS FDISK, OS/2 FDISK) Warning: invalid flag 0x0000 of partition table 4 will be corrected by w(rite) Command (m for help): n Command action e extended p primary partition (1-4) p Partition number (1-4): 1 First cylinder (1-51199, default 1): Using default value 1 Last cylinder or +size or +sizeM or +sizeK (1-51199, default 51199): Using default value 51199 Command (m for help): w The partition table has been altered! Calling ioctl() to re-read partition table. WARNING: Re-reading the partition table failed with error 22: Invalid argument. The kernel still uses the old table. The new table will be used at the next reboot. Syncing disks.
[root_at_oscdevdb1 ~]#
[root_at_oscdevdb1 ~]# /sbin/fdisk -l /dev/sda
Disk /dev/sda: 53.6 GB, 53687091200 bytes 64 heads, 32 sectors/track, 51200 cylinders Units = cylinders of 2048 * 512 = 1048576 bytes Device Boot Start End Blocks Id System /dev/sda1 1 51200 52428784 83 Linux
[root_at_oscdevdb1 ~]# /sbin/fdisk -l /dev/sda1
Disk /dev/sda1: 53.6 GB, 53687074816 bytes 64 heads, 32 sectors/track, 51199 cylinders Units = cylinders of 2048 * 512 = 1048576 bytes Device Boot Start End Blocks Id System /dev/sda1p1 1 51199 52427760 83 Linux
[root_at_oscdevdb1 ~]#
I supposed to do it on sdai1 So, /dev/sda1 was a DISK6 in our diskgroup. Now, nothing happened yet. I mean, all 20 database are up and running so far and I got no alerts or anything that would give me clues about catastrophe. I don't know what to do, I am freaking out of course, nut I created critical 1 issue with Oracle Support. It's been 4 hours since I did that and an hour and a half that i opened P1 ticket... I am looking for any hope you could provide.. It's a 2 node cluster, RedHat4 64 bit.. please, people, tell me I will not need to rebuild RAC... thanks, M --
Received on Mon Apr 11 2011 - 18:27:46 CDT

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