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)
and for all hdisks
rmdev -l hdiskx
chdev -l hdiskx -a max_transfer=0x100000 -a queue_depth=90 -P
mkdev -l hdiskx
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.
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9 replies Latest Post - 2012-02-07T22:51:32Z by cggibbo
Pinned topic Problem setting max_transfer at VIO client
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Updated on 2012-02-07T22:51:32Z at 2012-02-07T22:51:32Z by cggibbo
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defremov 2700013T672 PostsACCEPTED ANSWER
Re: Problem setting max_transfer at VIO client2012-01-19T11:40:03Z in response to SystemAdminHello. 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 2700013T672 PostsACCEPTED ANSWER
Re: Problem setting max_transfer at VIO client2012-01-19T11:40:47Z 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 270003TXMM1 PostACCEPTED ANSWER
Re: Problem setting max_transfer at VIO client2012-01-20T10:43:34Z in response to SystemAdminHi
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.
Re: Problem setting max_transfer at VIO client2012-02-06T13:41:29Z in response to SystemAdminThank 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.
cggibbo 270000TMUJ17 Posts
Re: Problem setting max_transfer at VIO client2012-02-07T08:00:00Z in response to cggibboWe 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 270000TMUJ17 PostsACCEPTED ANSWER
Re: Problem setting max_transfer at VIO client2012-02-07T22:51:32Z in response to SystemAdminNo 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