Re: Logging Access to HDD

[Sebastian Biedermann <biedermann@seceng.informatik.tu-darmstadt.de>]

Am 19.04.2011 11:35, schrieb James Harper:
>> Dear List,
>>
>> I´m working in research and I tought this list could be
>> a good adress for my questions.
>>
>> I want to log the disk accesses of the virtual hvm instances running in Xen.
>> That means for the start I want to log the write querys of a running
>> domU instance in the dom0 instance.
>>
>> So I´m trying to modify the Xen 3.2.1 source code,
>> but actually I was not able to find a good entry point to do this.
>>
>> For now, I want to log the disk accesses of a running windows 7 domU
>> instance.
>> The best what could happenis that I could see even the source and target
>> of a hdd write query.
>>
>> Does anyone have an idea how I could do this on a good way?
>> Which Xen source file / function should I modify? Where is the best
>> entry point to do this?
> HVM access can either be emulated PCI IDE, or PV. For the emulated access you would hook into qemu, I think. For PV access you would need to hook into whatever block device backend you are using.
>
> Do you just want to count reads and writes, or do you want to log every single byte read/written?
>
> James

I dont need to log every single byte, it would be enough to know which 
file is accessed by the domU inside its image.
So when I use HVM I need to modify qemu and not the xen source?

thanks

-- 
Sebastian