Re: VM(s) producing load on a particular datastore? (GUI?)

There's not really any out of the box comprehensible GUI tool suitable for what you want (including vCOPS), but tools like (r)esxtop can produce CSV-exports you can use to graph with etc.

Besides (r)esxtop, here's a PowerCLI example for determining IOPS per VM on a particular datastore (realtime, last hour averages):

Get-Datastore DataStore1Name | Get-VM | Sort |

Select @{N="VM Name"; E={$_.Name}},

@{N="AvgReadIOPS"; E={[math]::round((Get-Stat $_ -stat "datastore.numberReadAveraged.average" -RealTime | Select -Expand Value | measure -average).Average, 1)}},

@{N="AvgWriteIOPS"; E={[math]::round((Get-Stat $_ -stat "datastore.numberWriteAveraged.average" -RealTime | Select -Expand Value | measure -average).Average, 1)}} |

Sort AvgWriteIOPS -Desc |

Format-Table -autosize

Or over a longer period of time in the past (might need custom vCenter collection interval):

$DaysBack = -1

Get-Datastore DataStore1Name | Get-VM | Sort |

Select @{N="VM Name"; E={$_.Name}},

@{N="AvgReadIOPS"; E={[math]::round((Get-Stat $_ -stat "datastore.numberReadAveraged.average" -Start (Get-Date).AddDays($DaysBack) -Finish (Get-Date) | Select -Expand Value | measure -average).Average, 1)}},

@{N="AvgWriteIOPS"; E={[math]::round((Get-Stat $_ -stat "datastore.numberWriteAveraged.average" -Start (Get-Date).AddDays($DaysBack) -Finish (Get-Date) | Select -Expand Value | measure -average).Average, 1)}} |

Sort AvgWriteIOPS -Desc |

Format-Table -autosize

Sample output:

[...]