Re: VFS hot tracking: How to calculate data temperature?

[Zheng Liu <gnehzuil.liu@gmail.com>]

On Fri, Nov 02, 2012 at 02:38:29PM +0800, Zhi Yong Wu wrote:
> Here also has another question.
> 
> How to save the file temperature among the umount to be able to
> preserve the file tempreture after reboot?
> 
> This above is the requirement from DB product.
> I thought that we can save file temperature in its inode struct, that
> is, add one new field in struct inode, then this info will be written
> to disk with inode.
> 
> Any comments or ideas are appreciated, thanks.

Hi Zhiyong,

I think that we might define a callback function.  If a filesystem wants
to save these data, it can implement a function to save them.  The
filesystem can decide whether adding it or not by themselves.

BTW, actually I don't really care about how to save these data because I
only want to observe which file is accessed in real time, which is very
useful for me to track a problem in our product system.

Regards,
Zheng