<html xmlns:v="urn:schemas-microsoft-com:vml" xmlns:o="urn:schemas-microsoft-com:office:office" xmlns:w="urn:schemas-microsoft-com:office:word" xmlns:m="http://schemas.microsoft.com/office/2004/12/omml" xmlns="http://www.w3.org/TR/REC-html40"><head><meta http-equiv=Content-Type content="text/html; charset=us-ascii"><meta name=Generator content="Microsoft Word 14 (filtered medium)"><style><!--
/* Font Definitions */
@font-face
{font-family:SimSun;
panose-1:2 1 6 0 3 1 1 1 1 1;}
@font-face
{font-family:SimSun;
panose-1:2 1 6 0 3 1 1 1 1 1;}
@font-face
{font-family:Calibri;
panose-1:2 15 5 2 2 2 4 3 2 4;}
@font-face
{font-family:Tahoma;
panose-1:2 11 6 4 3 5 4 4 2 4;}
@font-face
{font-family:Consolas;
panose-1:2 11 6 9 2 2 4 3 2 4;}
@font-face
{font-family:"\@SimSun";
panose-1:2 1 6 0 3 1 1 1 1 1;}
/* Style Definitions */
p.MsoNormal, li.MsoNormal, div.MsoNormal
{margin:0in;
margin-bottom:.0001pt;
font-size:11.0pt;
font-family:"Calibri","sans-serif";
color:black;}
a:link, span.MsoHyperlink
{mso-style-priority:99;
color:blue;
text-decoration:underline;}
a:visited, span.MsoHyperlinkFollowed
{mso-style-priority:99;
color:purple;
text-decoration:underline;}
pre
{mso-style-priority:99;
mso-style-link:"HTML Preformatted Char";
margin:0in;
margin-bottom:.0001pt;
font-size:10.0pt;
font-family:"Courier New";
color:black;}
span.EmailStyle17
{mso-style-type:personal;
font-family:"Calibri","sans-serif";
color:windowtext;}
span.HTMLPreformattedChar
{mso-style-name:"HTML Preformatted Char";
mso-style-priority:99;
mso-style-link:"HTML Preformatted";
font-family:Consolas;
color:black;}
span.EmailStyle20
{mso-style-type:personal-reply;
font-family:"Calibri","sans-serif";
color:#1F497D;}
.MsoChpDefault
{mso-style-type:export-only;
font-size:10.0pt;}
@page WordSection1
{size:8.5in 11.0in;
margin:1.0in 1.0in 1.0in 1.0in;}
div.WordSection1
{page:WordSection1;}
--></style><!--[if gte mso 9]><xml>
<o:shapedefaults v:ext="edit" spidmax="1026" />
</xml><![endif]--><!--[if gte mso 9]><xml>
<o:shapelayout v:ext="edit">
<o:idmap v:ext="edit" data="1" />
</o:shapelayout></xml><![endif]--></head><body bgcolor=white lang=EN-US link=blue vlink=purple><div class=WordSection1><p class=MsoNormal><span style='color:#1F497D'>Thanks Suni. Yes the terminology should be super block corruption.<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>I checked with my colleague they said the ISCSI server suffered a power outage yesterday so they rebooted it.<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>Given it was under heavy usage because of many VM running on, I guess this may be the cause. now I am trying to recover it<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p><div><div style='border:none;border-top:solid #B5C4DF 1.0pt;padding:3.0pt 0in 0in 0in'><p class=MsoNormal><b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif";color:windowtext'>From:</span></b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif";color:windowtext'> Sunil Mushran [mailto:sunil.mushran@oracle.com] <br><b>Sent:</b> Wednesday, October 12, 2011 10:08 AM<br><b>To:</b> Frank Zhang<br><b>Cc:</b> 'ocfs2-users@oss.oracle.com'<br><b>Subject:</b> Re: [Ocfs2-users] Partition table crash, where can I find debug message?<o:p></o:p></span></p></div></div><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Not sure what you mean by a partition table crash. Is it that someone<br>overwrote the partition table on the iscsi server? That's what it looks<br>like. If mount cannot detect the fs type, then it means atleast superblock<br>corruption. And such corruptions typically caused by external entities.<br>Stray dd perhaps.<br><br>Did you try recovering the superblock using one of the the backups?<br>fsck.ocfs2 -r [1-6] /dev/sdX ?<br><br>On 10/11/2011 07:04 PM, Frank Zhang wrote: <o:p></o:p></p><p class=MsoNormal>Hi Experts, recently I observed a partition table crash that made me really scared.<o:p></o:p></p><p class=MsoNormal>I have two OVM servers sharing OCFS2 over iscsi, after running a bunch of VMs for a while, all VMs were gone and I saw the mount points of OCFS2 gone on both hosts.<o:p></o:p></p><p class=MsoNormal>Then I tried to mount it again, the iscsi device crashed by saying “please specify filesystem type”. I checked dmesg but there is nothing useful except <o:p></o:p></p><p class=MsoNormal> <o:p></o:p></p><p class=MsoNormal>“SCSI device sdc: drive cache: write back<o:p></o:p></p><p class=MsoNormal>sdc: unknown partition table<o:p></o:p></p><p class=MsoNormal>sd 2:0:0:1: Attached scsi disk sdc<o:p></o:p></p><p class=MsoNormal>sd 2:0:0:1: Attached scsi generic sg3 type 0<o:p></o:p></p><p class=MsoNormal>OCFS2 Node Manager 1.4.4<o:p></o:p></p><p class=MsoNormal>OCFS2 DLM 1.4.4<o:p></o:p></p><p class=MsoNormal>OCFS2 DLMFS 1.4.4<o:p></o:p></p><p class=MsoNormal>OCFS2 User DLM kernel interface loaded<o:p></o:p></p><p class=MsoNormal>connection1:0: detected conn error (1011)”<o:p></o:p></p><p class=MsoNormal> <o:p></o:p></p><p class=MsoNormal>basically after logging into ISCSI device on both hosts, I created soft links of /dev/ovm_iscsi1 pointing to device node under /dev/disk/by-path/real_isci_device, then I formatted /dev/ovm_iscsi1 to OCFS2 and mounted them to somewhere(of course I configured /etc/ocfs2/cluster.conf and made o2cb correctly start).<o:p></o:p></p><p class=MsoNormal>Could somebody tell me where to get more debug info to trace the problem? This is really scared considering I may lose all my VMs because of the silent crash.<o:p></o:p></p><p class=MsoNormal> <o:p></o:p></p><p class=MsoNormal>And is there any way to recover the partition table? Thanks<o:p></o:p></p><p class=MsoNormal> <o:p></o:p></p><p class=MsoNormal> <o:p></o:p></p><p class=MsoNormal> <o:p></o:p></p><pre><o:p> </o:p></pre><pre><o:p> </o:p></pre><pre>_______________________________________________<o:p></o:p></pre><pre>Ocfs2-users mailing list<o:p></o:p></pre><pre><a href="mailto:Ocfs2-users@oss.oracle.com">Ocfs2-users@oss.oracle.com</a><o:p></o:p></pre><pre><a href="http://oss.oracle.com/mailman/listinfo/ocfs2-users">http://oss.oracle.com/mailman/listinfo/ocfs2-users</a><o:p></o:p></pre><p class=MsoNormal><span style='font-size:12.0pt;font-family:"Times New Roman","serif"'><o:p> </o:p></span></p></div></body></html>