Performance for p550 with VIOS and many LPARs - Aix

This is a discussion on Performance for p550 with VIOS and many LPARs - Aix ; Hi all, I'm thinking about new configuration my p550 servers. I have p550 with 48RAM + 8CPU and 8 disks. I don't have RAID controller. My server has VIOS + 20-40 LPARs I mirrored VIOS on two disks. I have ...

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Thread: Performance for p550 with VIOS and many LPARs

  1. Performance for p550 with VIOS and many LPARs

    Hi all,

    I'm thinking about new configuration my p550 servers.

    I have p550 with 48RAM + 8CPU and 8 disks. I don't have RAID controller.

    My server has VIOS + 20-40 LPARs

    I mirrored VIOS on two disks.
    I have 6 disks 300GB for split to all 20-40 LPARs.
    What do you think how can I configure disks from performance point of view?

    1. 3 disks in VG + 3 in mirror (save configuration)
    2. 6 disk in huge VG (if one disk wiil be failed I lost only a few
    LPARs, right?)
    3. 6 disk in VG with stripping (if one disk will be failed I lost the
    data, right?)

    Would you give me a hand with choosing the best configuration for VIO
    server?

    Best,

    Luke

  2. Re: Performance for p550 with VIOS and many LPARs

    On Thu, 24 May 2007 22:27:07 +0200, luke wrote:

    >I have p550 with 48RAM + 8CPU and 8 disks. I don't have RAID controller.
    >My server has VIOS + 20-40 LPARs ... I mirrored VIOS on two disks.


    Good.

    >I have 6 disks 300GB for split to all 20-40 LPARs.
    >What do you think how can I configure disks from performance point of view?


    Regardless of your configuration you're going to have a very limited
    infrastructure. Look at it this way -- assume 20 LPARs and six 15K
    300GB disks. Each disk is capable (downhill with favorable winds) of
    150 random I/O per second. 20 LPARs that gives 7.5 I/O per second per
    disk per LPAR or, with 6 disks, 45 IOPS per LPAR. That's the maximum
    rate. You shouldn't seriously consider running more than half that in
    any sustained "production" situation.

    Similarly, you're going to have to carve up memory and that leaves you
    with about 2GB per LPAR. This may be enough -- I remember when
    everything ran in 32K -- or it may not be. If it's not, you better not
    even consider paging because, per the discussion above, this will die
    on the vine.

    You should look realistically evaluate your workload and determine if
    this is a reasonable hardware configuration. If this is just an
    experimental environment or for your own education, sure, it'll work.

    >1. 3 disks in VG + 3 in mirror (save configuration)
    >2. 6 disk in huge VG (if one disk wiil be failed I lost only a few
    >LPARs, right?)
    >3. 6 disk in VG with stripping (if one disk will be failed I lost the
    >data, right?)


    Logical volumes on the VIOS used as virtual disks cannot be mirrored,
    striped, or have bad block relocation enabled. See
    http://www14.software.ibm.com/webapp...ation/faq.html

    Mirroring would have to be done by the Client LPARs.

    -- David

  3. Re: Performance for p550 with VIOS and many LPARs

    Hi David,

    Thank you very much for you reply.

    [...]

    >>I have 6 disks 300GB for split to all 20-40 LPARs.
    >>What do you think how can I configure disks from performance point of view?

    >
    >
    > Regardless of your configuration you're going to have a very limited
    > infrastructure. Look at it this way -- assume 20 LPARs and six 15K
    > 300GB disks. Each disk is capable (downhill with favorable winds) of
    > 150 random I/O per second. 20 LPARs that gives 7.5 I/O per second per
    > disk per LPAR or, with 6 disks, 45 IOPS per LPAR. That's the maximum
    > rate. You shouldn't seriously consider running more than half that in
    > any sustained "production" situation.
    >
    > Similarly, you're going to have to carve up memory and that leaves you
    > with about 2GB per LPAR. This may be enough -- I remember when
    > everything ran in 32K -- or it may not be. If it's not, you better not
    > even consider paging because, per the discussion above, this will die
    > on the vine.
    >
    > You should look realistically evaluate your workload and determine if
    > this is a reasonable hardware configuration. If this is just an
    > experimental environment or for your own education, sure, it'll work.
    >
    >>1. 3 disks in VG + 3 in mirror (save configuration)
    >>2. 6 disk in huge VG (if one disk wiil be failed I lost only a few
    >>LPARs, right?)
    >>3. 6 disk in VG with stripping (if one disk will be failed I lost the
    >>data, right?)


    I didn't write that this p550 has 20LPARs but will be upgrade with
    disks, too.

    2xdisks 143 (15rpm) for VIO Server with mirror
    5xdisks 300 (10rpm) for 20 LPARs. Four LPARs per one disks. Database was
    installed on other server (with fast I/O).
    1xdisk 300 (10rpm) for evenutally mirror for LPARs partition

    > Logical volumes on the VIOS used as virtual disks cannot be mirrored,
    > striped, or have bad block relocation enabled. See
    > http://www14.software.ibm.com/webapp...ation/faq.html


    Thanks. I didn't know it

    By the way. In VIO server I can see option 'any partition can share this
    disk' or something like that (I write from memory). How can use it? I
    must configure GPFS and share vhost for LPARs?

    Best,

    Luke

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