Aix 6.1 Understanding Hard Drive PP's

Posted on 2012-08-23
Last Modified: 2012-08-24
My Aix 6.1 server has a mirror 73GB hard drive.  When I type in lsvg rootvg it states that I have 546 total PP's and 9 free..

When I run the lsvg rootvg command it stats that total PP's is 1638 and free is 27..

I'm trying to figure out in MB or GB how much unallocates hard drive space I actually have..

Can someone please help me understand this
Question by:compdigit44
    LVL 68

    Expert Comment

    lsvg shows the number of megabytes in parentheses just following the PP numbers.

    Further, it shows the size of a single PP in Megabytes on the upper right.

    Please remember that with a mirrored LV you need two or three PPs to enlarge the LV by one LP:

    Number of required physical partitions = number of desired logical partitions * number of copies.

    Please reread your question. How come that exactly the same command would show such disparate results?
    LVL 19

    Author Comment

    When I type in the lsvg rootvg command

    For total PP 1638 (209664 MB) yet I have a 73 GB mirror???
    LVL 68

    Accepted Solution

    Please don't make me nervous with this abundant use of question marks. I hate it.

    PPs have nothing to do with mirroring.

    With three 73 GB disks you indeed have that many PPs (1638 ~ 210 GB).

    As I told you, with mirroring a logical partition (LP) can use up to 3 PPs so with a three-way mirror you have  1638 PPs / 3 copies = 546 LPs (~ 70 GB) useable space.

    PPs are raw space on disk, LPs are useable space after mirroring.

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