Re: EM 12c VMware Plugin/monitoring
Date: Fri, 9 Aug 2013 11:07:08 -0400
Message-Id: <5A242A10-2402-4369-A9F5-F60E960E952E_at_bluemedora.com>
There are a number of reasons why it's dangerous to rely only on the Oracle OMA / host target to monitor hosts virtualized on VMware. The primary reason is the Oracle Management Agent (OMA) / host target is not aware that the server is virtualized and the metrics it reports can (and will) be inadequate at best or possibly just inaccurate. Examples of this include: The OMA isn't aware of VMware memory / CPU limits applied to the Virtual Machine - For example, the OS is assigned 16GB of RAM and 8GB of it is currently in use. Everything looks good from the OMA perspective…, however, there is a VMware Memory Limit assigned to the VM (which the OS and OMA can’t see) that limits the amount of RAM the Hypervisor will ever assign to the virtual machine to 8GB. Using just the OMA it looks like the virtual machine is roughly 50% utilized… in reality it's not going to get any more RAM from the ESX hypervisor and if your DB/App needs more than 8GB, swapping is going to occur and dramatically affect performance. Again, no amount of OS level tooling (such as the OMA, or Linux Top, or Windows Task Manager) is going to have any evidence as to why this slowdown is occurring. The OMA / host target and the operating system itself has zero-visibility into what other virtual machines are running on the same ESX hypervisor and those other workloads can drain the system of resources - Great example of this is with the OMA / host target you see that your Virtual Machine is only 15% CPU utilized. Everything looks good from the traditional tooling (Linux Top, Windows Tasks Manager, etc) as well… however, the server is performing extremely slowly. What you can't see is that another virtual machine on the same ESX hypervisor is eating up all the CPU cycles for the physical hardware and although you think your virtual machine is only 15% CPU utilized the ESX server has no CPU left to give it… in other words if your App/DB needs more CPU cycles you’re in trouble.
Finally, the OMA/host target typically does not have visibility into the Storage layer of your VM running on VMWare. While the OMA reports the disk of your virtual machine is only 60% utilized, the reality is that machine's virtual disks are sitting on a SAN somewhere that is 99% utilized. Again, none of the traditional OS tools (or the OMA) can see beyond what the operating system "thinks" it sees.
Those are a few examples of why you are asking for trouble virtualizing your Oracle workloads on VMware only using the OMA / host target and/or traditional OS monitoring tools that aren't VMware aware.
Thanks, Nathan
Nathan Owen | Blue Medora | www.bluemedora.com | blog.bluemedora.com
On Aug 8, 2013, at 11:59 AM, Dba DBA <oracledbaquestions_at_gmail.com> wrote:
> http://apex.oracle.com/pls/apex/f?p4841:11
> I have not installed EM 12c yet. I have literally not had the hardware to
> standup another DB to host this. Some new hardware is being setup now and I
> want to get EM running (its just a dev/test environment). So asking this
> site unseen. I can't mess around with it until the hardware is setup.
>
> We run everything on VMWare esxi VMs. With the new hardware there will
> about about a dozen hosts and 80+ VMs along with a mid-range SAN (I forget
> the exact version). All I have to monitor the VMs with is the free Vsphre
> client. The biggest problem with this is that I don't get a dashboard for
> all the hosts. I have to log into each separately. So this can be a serious
> hassle. VM makes you pay for a tool that does that and this is contracting
> and the client won't pay.
>
> Not sure if its worth looking at the VMware plugin for EM? anyone use it?
> At first glance it just looks like its Vsphere plugged into EM with a few
> prettier pictures. That isn't useful to me. This would only be useful if I
> could get the data added to my dashboard so I can go to my hosts screen and
> keep an eye on all of them from one screen and set up email alerts., etc...
> The Admin work here is not real heavy lifting, but it can be tedious. This
> is a smaller team so there is only 1 SA and he is spread over 2 projects.
>
> any other options than this for monitoring the actually VMWare hosts from
> with in EM 12c? Think with the new dashboard configuration, I can organize
> my VMs in the dashboard and group them by host manually, but I don't know
> if there is a way to get host level metrics off of EM ( can I install an
> oracle agent on a Vmware OS on the host? )
>
> This isn't mission critical. Just trying to make some work less tedious.
>
>
> --
> http://www.freelists.org/webpage/oracle-l
>
>
-- http://www.freelists.org/webpage/oracle-lReceived on Fri Aug 09 2013 - 17:07:08 CEST