Re: Question about hiding disks from smit

From: Bob Booth - CITES (booth_at_UIUC.EDU)
Date: 08/26/05

  • Next message: Ford, Phillip: "Re: Question about hiding disks from smit" 
    Date:         Fri, 26 Aug 2005 11:26:30 -0500
To: aix-l@Princeton.EDU

    On Fri, Aug 26, 2005 at 11:45:04AM -0400, Ford, Phillip wrote:
    > Most of my system are for Oracle databases. Most are AIX 5.2 but I do have
    > some 4.3.3 still. Up until now we have used raw logical volumes or cooked
    > file systems with oracle. During the process of using smit to create or
    > extend volume groups, smit will only show the disks that are not being used.
    > This is nice and makes sure that an administrator does not try and use a
    > disk in two volume groups.
    >
    > Now the DBAs have decided to try and use the new Oracle 10g ASM (Automatic
    > Storage Management) feature of Oracle 10g. With this we give oracle control
    > of raw disks. We do this by making Oracle owner of the raw device. Then
    > Oracle can use them as he wishes. The problem is that when a system
    > administrator goes into smit to create or extend a volume group he sees what
    > smit thinks are unused disks and this includes the ones used by Oracle ASM.
    > So now the administrator has to be careful and remember which disks are used
    > by Oracle directly and not use any of them for vg creation or extension.
    >
    > My question, is there something that I can do to the ODM to have smit think
    > that the Oracle disks are in use so that he will not show me these disks
    > during a vg create or extension? This must not affect Oracle though. I do
    > not know much about the ODM and have no idea what smit keys off of to tell
    > whether a disk is in use or not. Thanks in advance.

    No, smit uses a set of LVM commands to find all LV's to do operations on. The
    one you are most worried about is extendlv, since it will cause Oracle all kinds
    of grief. If an LV is open, you can't create a filesystem, or delete it.

    I have this same problem with TSM, since I use raw logical volumes for the
    database, log, and storage pools.

    Here is what I suggest:

    1. Keep fools that don't know the system off of it (if possible)
    2. Place your LV's in specficially named volume groups such as
            'OracleProdVG'
    3. Name your LV's 'hands off' names, such as OracleRawLV1
    4. Have a standard and documentation for the 'number 1's' that you can't
            keep off your system.

    Dinking with the ODM is always painful, since you don't know what is going to
    go tweaking it in the future, blowing your entire system out of the water.

    hth,

    bob

  • Next message: Ford, Phillip: "Re: Question about hiding disks from smit"

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