Subject: Re: Veritas Volume Replicator instead of DataGuard
From: Carel-Jan Engel <careljan@dbalert.eu>
To: binhpham15@hotmail.com
Cc: oracle-l@freelists.org
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Date: Wed, 12 Sep 2007 23:59:05 +0200
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Hi Binh,

In my opinion, there are numerous arguments to favour Data Guard over
disk/san/volume replication. Just to mention a few: 

     1. Much less bandwidth reuired: just redo vectors get sent over,
        not a full block/cluster/track for every redo wrtite, data file
        write, archive write, control file write....... 
     2. Configuring a delay in applying archives at the DR site protects
        for 'logical' errors as well. That has saved some asses of
        customers in the past 
     3. Applying the archives at the standby implies a sanity check of
        the archives themselves: a bit fallen over (whatever rare it is)
        in a disk block gets detected. 
     4. Independency of storage architecture: you can afford to have a
        smaller/slower/older SAN at the DR site, as long as you can
        store all database files. You can even afford to have no SAN but
        JBOD/NAS/DAS at the DR site, or just no SAN at all at both
        ends. 

Of course there are some arguments in favour of disk/san/volume
replication as well: 

     1. No Oracle license required at the DR site if you do not do the
        sanity checks more often than at 10 days per year. 
     2. One 'topic of expertise' needed for DR

I can't think of more right now, but maybe my mind is a little
biased ;-)

HTH

Best regards,

Carel-Jan Engel

===
If you think education is expensive, try ignorance. (Derek Bok)
===

On Wed, 2007-09-12 at 14:52 -0700, Binh Pham wrote:

> Any one who has used Veritas Volume Replicator in place of DataGuard for
> disaster recovery or failover setups?
> 
> Any issues or problems? Pro's and con's?
> 
> Thanks.
> 
> --
> http://www.freelists.org/webpage/oracle-l
> 
> 


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Hi Binh,<BR>
<BR>
In my opinion, there are numerous arguments to favour Data Guard over disk/san/volume replication. Just to mention a few: 
<OL TYPE=1>
    <LI TYPE=1 VALUE=1>Much less bandwidth reuired: just redo vectors get sent over, not a full block/cluster/track for every redo wrtite, data file write, archive write, control file write....... 
    <LI TYPE=1 VALUE=2>Configuring a delay in applying archives at the DR site protects for 'logical' errors as well. That has saved some asses of customers in the past 
    <LI TYPE=1 VALUE=3>Applying the archives at the standby implies a sanity check of the archives themselves: a bit fallen over (whatever rare it is) in a disk block gets detected. 
    <LI TYPE=1 VALUE=4>Independency of storage architecture: you can afford to have a smaller/slower/older SAN at the DR site, as long as you can store all database files. You can even afford to have no SAN but JBOD/NAS/DAS at the DR site, or just no SAN at all at both ends. 
</OL>
Of course there are some arguments in favour of disk/san/volume replication as well: 
<OL TYPE=1>
    <LI TYPE=1 VALUE=1>No Oracle license required at the DR site if you do not do the sanity checks more often than at 10 days per year. 
    <LI TYPE=1 VALUE=2>One 'topic of expertise' needed for DR
</OL>
I can't think of more right now, but maybe my mind is a little biased ;-)<BR>
<BR>
HTH<BR>
<BR>
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Best regards,<BR>
<BR>
Carel-Jan Engel<BR>
<BR>
===<BR>
If you think education is expensive, try ignorance. (Derek Bok)<BR>
===
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On Wed, 2007-09-12 at 14:52 -0700, Binh Pham wrote:
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<FONT COLOR="#000000">Any one who has used Veritas Volume Replicator in place of DataGuard for</FONT>
<FONT COLOR="#000000">disaster recovery or failover setups?</FONT>

<FONT COLOR="#000000">Any issues or problems? Pro's and con's?</FONT>

<FONT COLOR="#000000">Thanks.</FONT>

<FONT COLOR="#000000">--</FONT>
<FONT COLOR="#000000"><A HREF="http://www.freelists.org/webpage/oracle-l">http://www.freelists.org/webpage/oracle-l</A></FONT>


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