Re: Disk class filter driver for back-up mechanism by johnav
johnav
Mon Apr 25 01:48:44 CDT 2005
Are you sure you want to back up
> modified sectors on physical disks rather than blocks of data on logical
> volumes?
I need to back up modified sectors.
> Disk sector data (LBA + data) is best found from the output of the disk
> class driver, not the input.
So which method will be ideal one
1. Write an upper filter to Disk Class Driver and write a Completion
routine for IRP_MJ_WRITE to collect the modified sectors
2. Write lower filter to Disk Class Driver to collect modified
sectors.
regards
John
Mark Roddy <markr@hollistech.com> wrote in message news:<ugn8Kg0RFHA.3120@TK2MSFTNGP10.phx.gbl>...
> John wrote:
> > Hi All,
> >
> > I am trying to develop a backup tool. To give the maximum performance,
> > my plan is to write only modified blocks/sectors of source disk into
> > target disk since it was last backed up.
> >
> > How I can collect block/sector information from data write request
> > packet. Can a disk class upper filter solve this problem. Your ideas
> > are welcome
> >
> >
> > regards
> > John
> >
> Disk sector data (LBA + data) is best found from the output of the disk
> class driver, not the input. See the sources for disk.sys in the ddk. On
> the other hand, volume snapshot services already perform a similar,
> although volume based, function. Are you sure you want to back up
> modified sectors on physical disks rather than blocks of data on logical
> volumes?