Topic
9 replies Latest Post - ‏2012-02-07T22:51:32Z by cggibbo
SystemAdmin
SystemAdmin
1744 Posts
ACCEPTED ANSWER

Pinned topic Problem setting max_transfer at VIO client

‏2011-12-02T12:02:03Z |
Hi,

These days I am setting up an VIO server environment and I am starting to look at tuning the environment.

I am now looking at the hdisks and the attributes max_transfer and queue_depth and here I notice some strange things.

I start with shutting down the VIO Client so that I may change parameters at VIO Server.

Then i change the parameters at VIO Server like this (for each hdisk):

rmvdev -vtd vtscsixx
chdev -dev hdiskxx -perm -attr max_transfer=0x100000 queue_depth=90
mkvdev -vdev hdiskxx -dev vtscsixx -vadapter vhostx

This works. I am not able to use higher values than 0x100000, this is max.

Then I boot the VIO Client to set the parameters at that level as well.

For my Oracle VG (oravg) I do it like this:

unmount /ux (all disks belonging to Oracle)
varyoffvg oravg
exportvg oravg

and for all hdisks
rmdev -l hdiskx
chdev -l hdiskx -a max_transfer=0x100000 -a queue_depth=90 -P
mkdev -l hdiskx

and then
importvg -y oravg hdisk1

The problem is that max_transfer is still 0x40000.

I first thought that the values had not been registered at the VIO Server, but the values are OK there.

I try to run the command chdev -l hdiskx -a max_transfer=0x100000 to see what it says, and it says:

Method error (/etc/methods/chgdisk):
0514-018 The values specified for the following attributes
are not valid:
max_transfer Maximum TRANSFER Size

Since I am able to use 0x100000 at VIO Server, shouldnt I be able to use same parameter at the VIO Client?

In my head, it is the AIX OS at the VIO Client which is responsible for handling the IO and sending the request to the WaitQueue or the ServiceQueue, so i would think that it is important to set it at the VIO Client level? Or am i wrong? Do the parameter at Client level matter at all?

I am a little bit confused and I am hoping some of you may have a solution for me.
Updated on 2012-02-07T22:51:32Z at 2012-02-07T22:51:32Z by cggibbo
  • ned71
    ned71
    1 Post
    ACCEPTED ANSWER

    Re: Problem setting max_transfer at VIO client

    ‏2012-01-19T00:44:21Z  in response to SystemAdmin
    As a matter of interest, what levels of AIX and VIOS are you running. Also, which type of storage are you using?
    • SystemAdmin
      SystemAdmin
      1744 Posts
      ACCEPTED ANSWER

      Re: Problem setting max_transfer at VIO client

      ‏2012-01-19T07:02:45Z  in response to ned71
      Hi

      I forgot to mention some important info, sorry:

      AIX oslevel 6100-06-05-1115
      VIO ioslevel 2.2.0.12-FP24 SP-02
      Storage IBM System Storage DS4800
  • defremov
    defremov
    2 Posts
    ACCEPTED ANSWER

    Re: Problem setting max_transfer at VIO client

    ‏2012-01-19T11:40:03Z  in response to SystemAdmin
    Hello. I think that after this one, you had to reboot your server:
    $ chdev -dev hdiskxx -perm -attr max_transfer=0x100000 queue_depth=90

    Because -perm parameter makes changes in the ODM only. So, this means you haven't made any real changes to your hdisk devices yet. Hope that helps.
    • defremov
      defremov
      2 Posts
      ACCEPTED ANSWER

      Re: Problem setting max_transfer at VIO client

      ‏2012-01-19T11:40:47Z  in response to defremov
      > defremov wrote:
      > Hello. I think that after this one, you had to reboot your server:
      > $ chdev -dev hdiskxx -perm -attr max_transfer=0x100000 queue_depth=90
      >
      > Because -perm parameter makes changes in the ODM only. So, this means you haven't made any real changes to your hdisk devices yet. Hope that helps.
      By server, I meant VIOS, sorry.
  • pathfinder_dav
    pathfinder_dav
    1 Post
    ACCEPTED ANSWER

    Re: Problem setting max_transfer at VIO client

    ‏2012-01-20T10:43:34Z  in response to SystemAdmin
    Hi

    VIOS reboot is required when changing these values ​​to the hdisk. The help for chdev command in the VIOS indicated that -perm is used for devices that cannot be changed while in the available state.

    I recommend you read this article (is valid for other storage systems), for change others attributes (fc, fscsi and hdisk), before reboot VIOS.

    https://www.ibm.com/developerworks/mydeveloperworks/blogs/anthonyv/entry/xiv_and_aix_part_three_change_your_attributes1?lang=en

    Bye.
  • SystemAdmin
    SystemAdmin
    1744 Posts
    ACCEPTED ANSWER

    Re: Problem setting max_transfer at VIO client

    ‏2012-02-06T13:41:29Z  in response to SystemAdmin
    Thank you all for your answers.

    I will try again next time I am allowed to take down our systems and of course let you know the results.

    For now, I must wait since a couple of our AIX LPARs is very busy and I have to wait for readysignal.

    Regards

    Vetle
  • cggibbo
    cggibbo
    17 Posts
    ACCEPTED ANSWER

    Re: Problem setting max_transfer at VIO client

    ‏2012-02-07T03:09:44Z  in response to SystemAdmin
    Does the LPAR have a virtual optical device assigned to it ?(e.g. vtopt0/cd0)
    • SystemAdmin
      SystemAdmin
      1744 Posts
      ACCEPTED ANSWER

      Re: Problem setting max_transfer at VIO client

      ‏2012-02-07T08:00:00Z  in response to cggibbo
      We used optical device earlier, connected it through the virtual storage managment of VIO server, but disconnected it after use. So the optical device is no longer connected to any LPAR.
      • cggibbo
        cggibbo
        17 Posts
        ACCEPTED ANSWER

        Re: Problem setting max_transfer at VIO client

        ‏2012-02-07T22:51:32Z  in response to SystemAdmin
        No entirely sure if this will help, but take a look at the following post: https://www.ibm.com/developerworks/mydeveloperworks/blogs/cgaix/entry/can_t_change_max_transfer_for_vscsi_hdisk1?lang=en