Re: ASM diskmanagement and AIX 5.3

<erikw_nl_at_yahoo.com> wrote in message
news:1146483899.616571.94220_at_i39g2000cwa.googlegroups.com...
> Hi,
>
> We are using Oracle/RAC 10GR2 with ASM for disk management of diskspace
>
> used by the database. ASM requires that the disks are NOT included in a
>
> volume group and also uses the first block of the disk to store
> essential information. RAC 10GR2 does not need HACMP anymore.
> This setup imposes a serious problem for AIX systemmanagement:
> 1) It is difficult to distinguish disks on the AIX servers since they
> are not part of a volume group.
> 2) The usage of the first block by Oracle implies that chdev may not be
>
> used to create a PVID, since chdev overwrites the first block. If chdev
>
> is being used on a ASM disk, Oracle can not read that disk, and the
> database is lost.
> 3) Since ASM disks are writable by all servers in the cluster,
> reserve_policy is switched off, the probability that a disk is by
> accident used for a volume group is not unthinkable, with fatal
> consequences for the database.
> 4) Changes in SAN configuration may imply that existing devices have to
>
> be rearranged with rmdev. Rmdev removes disk devices and other devices
> nodes in /dev having equal major/minor number. Using sybolic names for
> hdisk devices in the Oracle database by creating devices nodes in /dev
> is not a viable option.
>
> Question:
> Does anybody recognise these issues, and is there a workaround so that
> ASM gets better integrated into standard AIX system management ?.
>
> Thanks in advance.
>
>
> Erik
>

yes - i've seen this happen too...
A LUN used by ASM is added to a VG - resulting in corruption.

This is what I've heard - so I might be wrong here - if so, please elaborate because
I'm also very interested in this issue : Normally ASMlib should take care of this - Oracle relies on the vendors to provide OS specific implementations of ASMlib - however, none have done so and they have taken Oracle's linux implementation without really
bothering. That means that :
- it works fine on linux
- might not work as expected on commercial unices ... Received on Mon May 01 2006 - 07:46:12 CDT