It could be a KVM bug, but it is a stretch, as supposedly the host platform has
already been vetted by the app maker.
--- mike t.
________________________________
From: Paolo Falcone <[email protected]>
To: The Main Philippine Linux Users' Group (PLUG) Discussion List
<[email protected]>
Sent: Tuesday, 2 July 2013, 20:26
Subject: Re: [plug] strange app behavior
I tend to believe the consultants in your case as KVM and class-1 hypervisors
like Xen or ESXi behave differently. In the case of VMware, ESXi is essentially
the only layer between the guest OS and the bare metal, compared to KVM wherein
the hypervisor is a full-blown Linux server.
Seems like a bug on KVM.
On Jul 2, 2013 8:04 PM, "Mike Tinsay" <[email protected]> wrote:
>Settings for both the host and guest were more than the recommended settings
>of the app maker.
>
>Actually there was lots of available memory and cpu utilization was below 10%
>when the app behaved badly.
>
>The vendor is claiming that they ran the same VM image on a VMWare ESX host
>without problem. I only have their word on this though.
>
>
>
>Zak Elep <[email protected]> wrote:
>
>>On Tue, Jul 2, 2013 at 9:47 AM, Michael Tinsay <[email protected]> wrote:
>>> I have this baffling situation... Our consultants are installing their very
>>> expensive piece of Java app running under Tomcat and RHEL 6. The whole
>>> thing is in a VM guest. Here's the thing, their app segfaults if the VM is
>>> a KVM guest running under a RHEL 6 host (and even an Ubuntu 12.04 host).
>>> They claim (I wasn't there personally) that their product runs ok for the
>>> same VM guest image running under VMWare ESX.
>>>
>>> Has anybody run into a similar situation? Is there a techincal explanation
>>> of why a Java app would segfault if the VM host is KVM as against an ESX
>>> host?
>>
>>My wild guess: Java memory ballooning differently in KVM versus ESX.
>>You might have to tune the KVM memory ballooning in your VM (I'm
>>guessing you're using libvirt, right, given that you're on RHEL?)
>>
>>Also, check the other obvious suspects (e.g. Tomcat memory settings,
>>badly-set OS sysctls, open file limits and the like.)
>>
>>
>>Cheers,
>>
>>Zakame
>>
>>--
>>Zak B. Elep || zakame.net
>>1486 7957 454D E529 E4F1 F75E 5787 B1FD FA53 851D
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_________________________________________________
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