[cisco-voip] CallManager Backup using Windows 2000 Backup

[Wes Sisk]

Hi Hauke,

Replication becomes a problem because both DCD and SQL replication use a
form of transactional replication.

Background:
Pub and Sub agree at time T that the contents of both databases match.
Then, every change that takes place on the pub is copied to the distribution
database and stamped with a monotonically increasing number.   Subscribers
connect to the distribution database and say "the last transaction I
received was X, please give me any new transactions". This "last
successfully replicated transaction identifier" is known as an LSN in SQL.

Application:
You have a pub/sub up and working.  The LSN is X.  You take the pub down and
ghost it.  The ghost copy stores LSN X.  You put the publisher back into
production.  It replicates with the subscriber for a while so the LSN
becomes X+10.  You decide to backout to the ghost image for some reason.
The ghosted pub comes back online with LSN=X.  The subscriber attempts to
replicate and reports it last replicated LSN=X+10.  SQL knows the
replication is now out of synch and stops replicating until you redo the
subscription (this copies a fresh snapshot of the database from pub to sub
and resets all LSNs).

/Wes


> -----Original Message-----
> From: Hauke Krull [mailto:hk at netuse.de]
> Sent: Thursday, June 10, 2004 6:23 AM
> To: Wes Sisk
> Cc: cisco-voip at puck.nether.net
> Subject: Re: [cisco-voip] CallManager Backup using Windows 2000 Backup
>
>
> Hello!
>
> Wes Sisk schrieb:
> > Keep in mind that if it's a cluster SQL replication and DCD
> > replication will be broken after a ghost restore.  ghost
> backup/restore is
> > not really supported by Cisco, but it has worked well in the field.
>
> Why is this a problem with a cluster?
>
>
> As far as I know, the HP ProLiant DL320 has a hardware IDE-RAID
> on board, and
> therefor the MCS7825 should have it also.
> Is it possible (and allowed from Cisco) to use this hardware Raid
> for cloning
> the main disc before updates?
>
> Best regards
>  Hauke Krull
> --
> Dipl.-Phys. Hauke Krull
> NetUSE AG
> Dr.-Hell-Straße, D-24107 Kiel, Germany
> Fon: +49 431 2390 400  --  Fax: +49 431 2390 499