Sunil and Saar - thanks for the quick replies!!<br><br>Quick follow-up question: would the 11g asmcmd "md_backup" command also be able to quickly rebuild all of the disk header information without losing any data?
<br><br><br><div><span class="gmail_quote">On 12/13/07, <b class="gmail_sendername">Saar Maoz</b> <<a href="mailto:Saar.Maoz@oracle.com">Saar.Maoz@oracle.com</a>> wrote:</span><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
<br>To avoid confusion, the paragraph I wrote is in context of ASM's<br>management of superblock, not OCFS2. OCFS2 was already responded to by<br>Sunil in another reply.<br><br>Regards,<br><br>Saar.<br><br>--<br> __ _ _ __ _ _ _ _ ___ _____________________________
<br> (( /\\ /\\ ||) |\V/| /\\ /\\ >/ Consulting Software Engineer<br> _))//-\\//-\\||\ |||||//-\\\\//<_ Oracle Corporation<br> HQ: 650.50-mixOS WK: 510.222.4224 <a href="mailto:Saar.Maoz@oracle.com">Saar.Maoz@oracle.com
</a> 4op441<br> \\\\\\\\50-64967\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\<br> ///Share your knowledge with others and compete with yourself///<br><br><br>On Thu, 13 Dec 2007, Saar Maoz wrote:<br><br>> Date: Thu, 13 Dec 2007 20:28:44 +0200 (Jerusalem Standard Time)
<br>> From: Saar Maoz <<a href="mailto:Saar.Maoz@oracle.com">Saar.Maoz@oracle.com</a>><br>> To: Jeremy Schneider <<a href="mailto:jeremy.schneider@ardentperf.com">jeremy.schneider@ardentperf.com</a>><br>
> Cc: <a href="mailto:ocfs2-users@oss.oracle.com">ocfs2-users@oss.oracle.com</a><br>> Subject: Re: [Ocfs2-users] superblock backups, ASM vs OCFS2<br>><br>> Jermey,<br>><br>> In <a href="http://11.1.0.7">
11.1.0.7</a> (and beyond) we will have a backup of the disk header (the first<br>> 4k). Prior to that, we have been able in most circumstances to reconstruct<br>> the disk header using KFED. KFED will still be the tool to restore the disk
<br>> header going forward, it will just be a simpler, more reliable procedure.<br>><br>> Regards,<br>><br>> Saar.<br>><br>> --<br>> __ _ _ __ _ _ _ _ ___ _____________________________
<br>> (( /\\ /\\ ||) |\V/| /\\ /\\ >/ Consulting Software Engineer<br>> _))//-\\//-\\||\ |||||//-\\\\//<_ Oracle Corporation<br>> HQ: 650.50-mixOS WK: 510.222.4224 <a href="mailto:Saar.Maoz@oracle.com">
Saar.Maoz@oracle.com</a> 4op441<br>> \\\\\\\\50-64967\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\<br>> ///Share your knowledge with others and compete with yourself///<br>><br>><br>> On Thu, 13 Dec 2007, Jeremy Schneider wrote:
<br>><br>>> Date: Thu, 13 Dec 2007 10:58:44 -0600<br>>> From: Jeremy Schneider <<a href="mailto:jeremy.schneider@ardentperf.com">jeremy.schneider@ardentperf.com</a>><br>>> To: <a href="mailto:ocfs2-users@oss.oracle.com">
ocfs2-users@oss.oracle.com</a><br>>> Subject: [Ocfs2-users] superblock backups, ASM vs OCFS2<br>>><br>>> [Also posted to Oracle-L]<br>>><br>>> Just wondering, does anyone know much about "superblock" backups in ASM vs
<br>>> OCFS2?<br>>><br>>> I ran into an interesting case a month or so back where someone had<br>>> accidentally tried to initialize their ASM disks with linux LVM... and<br>>> written the LVM headers to the disk. It was just a few bytes at the very
<br>>> top of the disk - but it was enough to totally hose ASM. Which started me<br>>> thinking, "if this was a filesystem then I'd have a backup superblock that<br>>> I<br>>> could recover". Who knows - maybe ASM has a backup of its header block -
<br>>> but it's all proprietary and if there's a tool that will recover an ASM<br>>> header then it's probably buried at Oracle support somewhere.<br>>><br>>> Looks like OCFS2 includes superblock backups since this patchset:
<br>>> <a href="http://lkml.org/lkml/2007/1/22/148">http://lkml.org/lkml/2007/1/22/148</a><br>>><br>>> Not sure if ckfs will recover them but since it's open source it'd be<br>>> trivial to put together a utility that would recover a superblock.
<br>>><br>>> This seems to me to be a great reason to choose OCFS2 over ASM. Recovering<br>>> a backup superblock is MUCH faster than recreating the entire volume and<br>>> restoring data from backup!!! I don't even know if you could use dd to try
<br>>> to backup your ASM disk headers - since it's proprietary I don't know<br>>> what's<br>>> in those blocks.<br>>><br>>> Anyone have any thoughts on this? Is there anything I'm missing here?
<br>>><br>>> Jeremy<br>>><br>>><br>>> --<br>>> Jeremy Schneider<br>>> Chicago, IL<br>>> <a href="http://www.ardentperf.com/category/technical">http://www.ardentperf.com/category/technical
</a><br>>><br>>><br>><br>_______________________________________________<br>Ocfs2-users mailing list<br><a href="mailto:Ocfs2-users@oss.oracle.com">Ocfs2-users@oss.oracle.com</a><br><a href="http://oss.oracle.com/mailman/listinfo/ocfs2-users">
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<a href="http://oss.oracle.com/mailman/listinfo/ocfs2-users">http://oss.oracle.com/mailman/listinfo/ocfs2-users</a><br><br></blockquote></div><br><br clear="all"><br>-- <br>Jeremy Schneider<br>Chicago, IL<br><a href="http://www.ardentperf.com/category/technical">
http://www.ardentperf.com/category/technical</a><br>