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jvm2016
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changing path selection policy to round robin

Hi Luc,

if you could suggest the prerequisites for changing path selection policy to round robin .

also from the attached screen shot if could suggest howmany extents this datastore has ??

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LucD
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That looks ok.

Just remove the WhatIf when you are sure the code is handling the correct LUNs.


Blog: lucd.info  Twitter: @LucD22  Co-author PowerCLI Reference

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LucD
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What do you mean by prerequisites?

Otherwise, changing the path selection to Round Robin hasn't changed.

See Re: changing path policy to round robin_powercli

From that screenshot I would guess 2, but to see exactly how many extents, check what $dr.ExtensionData.Info.Vmfs.Extent says.


Blog: lucd.info  Twitter: @LucD22  Co-author PowerCLI Reference

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jvm2016
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1:i m checking with storage team to see if round robin being suported at storage array which i think all moderan arrays are supporting

2:once it is configured i am running the following code to change to round robin

$vmfsdatastore=Get-Datastore|?{$_.Type -eq "VMFS"}|

$vmfsdatastore.count

  $vmfsdatastore|get-scsilun|?{$_.multipathpolicy -ne "roundrobin"}|Set-ScsiLun -MultipathPolicy RoundRobin -WhatIf

i think above two are sufficient enough to change multipath policy to round robin if yu could confirm one more time .

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LucD
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That looks ok.

Just remove the WhatIf when you are sure the code is handling the correct LUNs.


Blog: lucd.info  Twitter: @LucD22  Co-author PowerCLI Reference

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jvm2016
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thanks lun .one last thing for this post

below means it has one extent or no additional extent.

pastedImage_0.png

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LucD
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It has 1 extent.

The official description for Extent is "The list of partition names that comprise this disk's VMFS extents."


Blog: lucd.info  Twitter: @LucD22  Co-author PowerCLI Reference

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jvm2016
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thanks luc.

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jvm2016
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hi luc ,

if yu could suggest why the gollowing expression not working .i want to filter out t10.ata...  (local disks) from below output .

1:will it not accept wildcard * in this.

2:does it make any sense tp put round robin to local disks.

pastedImage_0.png

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LucD
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You should use -notlike instead of -ne


Blog: lucd.info  Twitter: @LucD22  Co-author PowerCLI Reference

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jvm2016
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thanks luc .for some reasons poreshell become slow hope its not infected with virus:smileylaugh:

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LucD
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The Get-ScsiLun cmdlet is terribly slow


Blog: lucd.info  Twitter: @LucD22  Co-author PowerCLI Reference

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jvm2016
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ohh

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jvm2016
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i think we are doing something wrong here we need to follow below

https://vmarena.com/how-to-change-all-luns-to-round-robin-policy-using-powercli/

if you can verfiy .i need to put each host in maintenance mode and do change in policy insted of directly going to datastores.

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LucD
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What do you mean by "we are doing something wrong"?

That post uses exactly the same code as is present in the link I shared earlier.

Why would the ESXi node need to be in maintenance mode?


Blog: lucd.info  Twitter: @LucD22  Co-author PowerCLI Reference

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jvm2016
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well my understanding it a typical path to storage device

consist of FC adapter ,cable ,connection to switch port and then storage contoller port .

roundrobin will utilize all paths if more than such combinations are avaiable .

so this post uses get-vmhost|get-scsilun

while we were discussing get-datastore|get-scsilun

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LucD
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Still don't see where we would be "wrong".

The Get-ScsiLun cmdlet accepts a VMHost or a Datastore parameter.


Blog: lucd.info  Twitter: @LucD22  Co-author PowerCLI Reference

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jvm2016
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well i am going with below which we decided its going to consider only vmfs datastore .

and no need for maintenace mode .i thought of checking this in test environemt but unfortunately i dont have .

and it should not impact any thing .if yu like to add anyother thing ...

$vmfsdatastore=Get-Datastore|?{$_.Type -eq "VMFS"}

$vmfsdatastore|get-scsilun|?{$_.multipathpolicy -ne "roundrobin" -and $_.canonicalname -notlike "t10.*"}||Set-ScsiLun -MultipathPolicy RoundRobin

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LucD
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No, go for it


Blog: lucd.info  Twitter: @LucD22  Co-author PowerCLI Reference

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jvm2016
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thanks Luc.

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jvm2016
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Hi Luc,

If you could help me suggesting the way to check whether following naa ids constitute datastores which are shared and not local .

pastedImage_1.png

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