Re: want to write a difference copy program to sync two VHDs in blktap

[R J <torushikeshj-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>]

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Hello,

I tried to copy the VHD in two ways. One by using xe vm-copy command and
other simple cp.
Im verifying the blocks with vhd-read command. VHD created by vm-copy has
different BAT and BITMAP than the original one.

But with cp the BAT and BITMAP remains same as its a mirror copy.
Still no big improvements.

-- Rishi

On Sat, Aug 11, 2012 at 4:26 AM, R J <torushikeshj-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote:

> Hello List,
>
> I'm using blktap on XCP 1.1 and developing a difference copy program for
> easy backup and remote archival.
>
> The idea is to read the BAT of VHD1 and sync it to BAT of VHD2 with BITMAP
> and the data blocks.
> Other way would be by adding a sha1 signature in each data block and
> comparing it with remote VHD.
>
> I tried to get some info from below programs but could not get required
> info about adding a sha1 sign of data block while writing it.
> Similar to ZFS this can be used to verify file integrity ?
> May be if someone can guide me about how to inject data while writing it
> in data block of VHD.
>
> Please advice.
>
> -- Rishi
>
> On Mon, Aug 6, 2012 at 9:26 PM, R J <torushikeshj-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote:
>
>> Hello List,
>>
>> I would like to know details of tapdisk-diff and tapdisk-stream
>> My aim is to find differences in two vhds and if possible sync them for
>> redundancy via a difference-copy program
>>
>> The idea is
>> - find the journel difference of src and dest VHD
>> - copy journel and modified blocks from src VHD to dest VHD for backup.
>>
>> in my case both are nfs vhds.
>>
>> Could anyone please provide me more info on above two programs ?
>>
>> - Rishi
>>
>
>

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