get-stat-realtime_powercli

[jvm2016]

Hi Luc,

i try to check one vm for average memory usage through get-stat

i found

while i checked the smethingthrough task manger

can you suggest something why these two dont match .

currently iam using reltime in get-stat.

[LucD]

Let me try to explain in a couple of lines.
A more detailed explanation would most probably take a couple of page or a compete chapter in a book :smileygrin:

• the Get-Stat cmdlet retrieves metrics from the PerformanceManager. That means from the outside (through the hypervisor).
• the mem.usage metric is a ratio of the active memory over the configured memory.
• the active memory number is estimated by the VMKernel (the hypervisor) based on the number of memory pages actively used during the measurement interval (20 seconds for Realtime)
• the memory percentage the Task manager shows is obtained inside the guest OS
• this also contains for example parts of the memory that the OS reserved uses for caching
• the amount the OS acquires for caching is relative to the total physical memory and what part of that physical memory is free
• the difference between 'actively used' and 'obtained', which is not necessarily used during the TaskManager measurement interval, is what most likely causes the different numbers you see

I hope this clarifies a bit

[jvm2016]

i got most of it :smileyhappy:

is there any way from powerclito get below (without changing stats level  but in realtime)

"the memory percentage the Task manager shows is obtained inside the guest OS "

[LucD]

You mean a shorter interval than 20 seconds?

If yes, that can be done with Get-EsxTop which uses by default a 5 second interval (but which is a bit more cumbersome to work with).

If you mean the performance metrics as the Task Manager shows, then you would need to look at the Get-Counter cmdlet.

This is not a PowerCLI cmdlet and needs to connect to the target over the network (which assumes such a connection exists) or needs to be run inside the Guest OS (think Invoke-VMScript).

[jvm2016]

i mean 20 seconds only as real time for get-stat is for 20seconds only(i think this is corect)

let me check get-counter .

[LucD]

Yes, the Realtime interval is a 20 seconds interval.