From mboxrd@z Thu Jan 1 00:00:00 1970 From: R J Subject: Re: want to write a difference copy program to sync two VHDs in blktap Date: Thu, 16 Aug 2012 22:09:56 +0530 Message-ID: References: Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="===============4116616164000896573==" Return-path: In-Reply-To: List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-api-bounces-GuqFBffKawuEi8DpZVb4nw@public.gmane.org Errors-To: xen-api-bounces-GuqFBffKawuEi8DpZVb4nw@public.gmane.org To: xen-api-GuqFBffKawuULHF6PoxzQEEOCMrvLtNR@public.gmane.org, xen-devel-GuqFBffKawuULHF6PoxzQEEOCMrvLtNR@public.gmane.org List-Id: xen-devel@lists.xenproject.org --===============4116616164000896573== Content-Type: multipart/alternative; boundary=047d7b621b148b2fe704c764b104 --047d7b621b148b2fe704c764b104 Content-Type: text/plain; charset=ISO-8859-1 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 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 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 >> > > --047d7b621b148b2fe704c764b104 Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable 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 comma= nd. VHD created by vm-copy has different BAT and BITMAP than the original o= ne.

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

-- Rishi

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

I'm using blktap on XCP 1.1 and developing a differe= nce 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 b= locks.
Other way would be by adding a sha1 signature in each data block and compar= ing 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 whi= le writing it.
Similar to ZFS this can be used to verify file integrity ?
May be if som= eone can guide me about how to inject data while writing it in data block o= f 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 t= hem 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 mor= e info on above two programs ?

- Rishi


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