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<p class="MsoNormal"><span style="color:#1F497D">See below: >>><o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D"><o:p> </o:p></span></p>
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<p class="MsoNormal"><b><span style="font-size:10.0pt;font-family:"Tahoma","sans-serif"">From:</span></b><span style="font-size:10.0pt;font-family:"Tahoma","sans-serif""> drbd-user-bounces@lists.linbit.com [mailto:drbd-user-bounces@lists.linbit.com]
<b>On Behalf Of </b>FDS | Forensik Data Services<br>
<b>Sent:</b> Friday, September 06, 2013 9:06 AM<br>
<b>To:</b> drbd-user@lists.linbit.com<br>
<b>Subject:</b> [DRBD-user] generation identifiers<o:p></o:p></span></p>
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<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"><span style="color:#1F497D">Hi there,<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D">I am involved in the aftermath of a split brain event (drbd 8.3.8). log files have given us several entries for
</span>drbd_sync_handshakes<span style="color:#1F497D">:</span><o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoListParagraph" style="text-indent:-.25in;mso-list:l2 level1 lfo2"><![if !supportLists]><span style="mso-list:Ignore">1.<span style="font:7.0pt "Times New Roman"">
</span></span><![endif]>Feb 28 07:10:04 san02 kernel: [ 1435.507176] block drbd1: self 384ACFA6DDE7F305:6EC706A11FB6AAEB:AD2868A6C65F20AA:D5016EA9D8E57175 bits:28397184 flags:0<o:p></o:p></p>
<p class="MsoListParagraph" style="text-indent:-.25in;mso-list:l2 level1 lfo2"><![if !supportLists]><span style="mso-list:Ignore">2.<span style="font:7.0pt "Times New Roman"">
</span></span><![endif]>Feb 28 07:10:04 san02 kernel: [ 1435.507472] block drbd0: self 8FFC8087A5A8ACDF:128A2EF7246101ED:00C719D52E8C2482:4EEC506B23021307 bits:225135 flags:0<o:p></o:p></p>
<p class="MsoListParagraph" style="text-indent:-.25in;mso-list:l2 level1 lfo2"><![if !supportLists]><span style="mso-list:Ignore">3.<span style="font:7.0pt "Times New Roman"">
</span></span><![endif]>Feb 28 07:11:36 san01 kernel: [4427691.562720] block drbd1: self 16DA13A883B368DA:6EC706A11FB6AAEA:AD2868A6C65F20AA:D5016EA9D8E57175 bits:3072 flags:0<o:p></o:p></p>
<p class="MsoListParagraph" style="text-indent:-.25in;mso-list:l2 level1 lfo2"><![if !supportLists]><span style="mso-list:Ignore">4.<span style="font:7.0pt "Times New Roman"">
</span></span><![endif]>Feb 28 07:11:36 san01 kernel: [4427691.562923] block drbd0: self 2DBF62FFC79BF9F4:128A2EF7246101EC:00C719D52E8C2483:4EEC506B23021307 bits:53722300 flags:0<o:p></o:p></p>
<p class="MsoListParagraph" style="text-indent:-.25in;mso-list:l2 level1 lfo2"><![if !supportLists]><span style="mso-list:Ignore">5.<span style="font:7.0pt "Times New Roman"">
</span></span><![endif]>Feb 28 07:17:46 san02 kernel: [ 1897.442652] block drbd0: self 8FFC8087A5A8ACDE:8A4BA5176FB14BAD:128A2EF7246101ED:00C719D52E8C2482 bits:21858 flags:0<o:p></o:p></p>
<p class="MsoListParagraph" style="text-indent:-.25in;mso-list:l2 level1 lfo2"><![if !supportLists]><span style="mso-list:Ignore">6.<span style="font:7.0pt "Times New Roman"">
</span></span><![endif]>Feb 28 07:17:46 san02 kernel: [ 1897.443239] block drbd1: self 384ACFA6DDE7F304:E9797096C25A015C:6EC706A11FB6AAEB:AD2868A6C65F20AA bits:24262845 flags:0<o:p></o:p></p>
<p class="MsoListParagraph" style="text-indent:-.25in;mso-list:l2 level1 lfo2"><![if !supportLists]><span style="mso-list:Ignore">7.<span style="font:7.0pt "Times New Roman"">
</span></span><![endif]>Feb 28 07:19:19 san01 kernel: [4428153.502129] block drbd0: self 8A4BA5176FB14BAC:0000000000000000:00C719D52E8C2483:4EEC506B23021307 bits:49588595 flags:0<o:p></o:p></p>
<p class="MsoListParagraph" style="text-indent:-.25in;mso-list:l2 level1 lfo2"><![if !supportLists]><span lang="DE-AT"><span style="mso-list:Ignore">8.<span style="font:7.0pt "Times New Roman"">
</span></span></span><![endif]><span lang="DE-AT">Feb 28 07:19:19 san01 kernel: [4428153.502363] block drbd1: self E9797096C25A015C:0000000000000000:AD2868A6C65F20AA:D5016EA9D8E57175 bits:0 flags:0<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="DE-AT"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D">The</span> Cluster <span style="color:#1F497D">
consists of 2 nodes</span> (san01 und san02) <span style="color:#1F497D">with two block devices</span> (drbd01 und drbd02)
<span style="color:#1F497D">running in dual primary with </span>OCFS2.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"><span lang="DE-AT" style="color:#1F497D">Analyzing</span><span lang="DE-AT"> Generation Identifier<span style="color:#1F497D">s oft he first handshake:</span><o:p></o:p></span></p>
<p class="MsoListParagraph" style="text-indent:-.25in;mso-list:l1 level1 lfo4"><![if !supportLists]><span lang="DE-AT" style="font-family:Symbol"><span style="mso-list:Ignore">·<span style="font:7.0pt "Times New Roman"">
</span></span></span><![endif]><span lang="DE-AT">Current UUIDs (1.-4.) <span style="color:#1F497D">
differ due to split brainsituation.</span><o:p></o:p></span></p>
<p class="MsoListParagraph" style="text-indent:-.25in;mso-list:l1 level1 lfo4"><![if !supportLists]><span style="font-family:Symbol"><span style="mso-list:Ignore">·<span style="font:7.0pt "Times New Roman"">
</span></span></span><![endif]><span lang="DE-AT"> </span>BitMap UUIDs (1.-4.) <span style="color:#1F497D">
are nearly identical</span>. <span style="color:#1F497D">Only the last digit differs from
</span>A-D. <span style="color:#1F497D">First</span> Historical UUID<span style="color:#1F497D">s</span> (1.-4.)
<span style="color:#1F497D">with</span> drbd1 <span style="color:#1F497D">are identical but differ for</span> block drbd0<span style="color:#1F497D">. Again only the last digit</span> (2
<span style="color:#1F497D">vs</span> 3).<o:p></o:p></p>
<p class="MsoListParagraph" style="text-indent:-.25in;mso-list:l1 level1 lfo4"><![if !supportLists]><span style="font-family:Symbol"><span style="mso-list:Ignore">·<span style="font:7.0pt "Times New Roman"">
</span></span></span><![endif]><span style="color:#1F497D">Second</span> Historical UUID (1.-4.)
<span style="color:#1F497D">for both</span> block-Devices <span style="color:#1F497D">
are identical meaning both devices have the same data set, or?</span><o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"><span lang="DE-AT" style="color:#1F497D">Questions</span><span lang="DE-AT">:<o:p></o:p></span></p>
<p class="MsoListParagraph" style="margin-left:41.25pt;text-indent:-.25in;mso-list:l0 level1 lfo6">
<![if !supportLists]><span style="font-family:Symbol;color:#1F497D"><span style="mso-list:Ignore">·<span style="font:7.0pt "Times New Roman"">
</span></span></span><![endif]><span style="color:#1F497D">Reason and meaning for differing last digit UUIDs are unknown. No information in the doc.</span><span style="color:#1F497D"><o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D">>>> I don’t know<o:p></o:p></span></p>
<p class="MsoListParagraph" style="text-indent:-.25in;mso-list:l0 level1 lfo6"><![if !supportLists]><span style="font-family:Symbol"><span style="mso-list:Ignore">·<span style="font:7.0pt "Times New Roman"">
</span></span></span><![endif]><span style="color:#1F497D">How can I see when the data sets were sync for the last time?</span><o:p></o:p></p>
<p class="MsoNormal"><span style="color:#1F497D">>>> Careful analysis of the logs<o:p></o:p></span></p>
<p class="MsoListParagraph" style="text-indent:-.25in;mso-list:l0 level1 lfo6"><![if !supportLists]><span style="font-family:Symbol"><span style="mso-list:Ignore">·<span style="font:7.0pt "Times New Roman"">
</span></span></span><![endif]><span style="color:#1F497D">Meaning of values for flags fe
</span>0<span style="color:#1F497D"> o</span>r 2?<o:p></o:p></p>
<p class="MsoNormal"><span style="color:#1F497D">>>> I don’t know<o:p></o:p></span></p>
<p class="MsoListParagraph" style="text-indent:-.25in;mso-list:l0 level1 lfo6"><![if !supportLists]><span style="font-family:Symbol"><span style="mso-list:Ignore">·<span style="font:7.0pt "Times New Roman"">
</span></span></span><![endif]><span style="color:#1F497D">Is it possible to decide which resource</span> (drbd0 or drbd1)
<span style="color:#1F497D">was primary by comparing UUIDs?</span><o:p></o:p></p>
<p class="MsoNormal"><span style="color:#1F497D">>>> You had dual primary – they were both primary. You’ll have to look at the data itself. For example if one file on one of the standalone drbd0 exists with a newer date, that file is likely more valid than
the other file. Depending on how and why you had dual primary without proper fencing in the first place, it may be trivial to determine which to keep and which to “discard-my-data”. If they are dual primary solely to provide live migration – AND – no live
migrations were taking place at the time of the split brain event, you are fairly safe using the resource (or disk image) to which a VM was pointed at the time of the “event”. If the file systems were shared by multiple hosts, you are stuck with file by file
analysis – and there are no promises that the newest file will contain all the data. You may need to do a row by row analysis depending on your applications.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D">>>> Again, without knowing the sharing and application logic in detail about your specific systems, split-brain analysis is impossible.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D">>>> hth and good luck!<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D">>>> (Get fencing working!!!!!, Get a current drbd installed!!)<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D">>>> Dan<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="DE-AT" style="color:#1F497D">Aprecciating your help.</span><span lang="DE-AT"><o:p></o:p></span></p>
<p class="MsoNormal"><span lang="DE-AT"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="DE-AT" style="font-size:10.0pt;font-family:"Arial","sans-serif";mso-fareast-language:DE-AT">--<br>
Mit freundlichen Grüßen<br>
<b>Ing. Mag. </b></span><b><span style="font-size:10.0pt;font-family:"Arial","sans-serif";mso-fareast-language:DE-AT">Horst Greifeneder<br>
</span></b><span style="font-size:10.0pt;font-family:"Arial","sans-serif";mso-fareast-language:DE-AT">(fds)
<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Arial","sans-serif";mso-fareast-language:DE-AT"> <o:p></o:p></span></p>
<p class="MsoNormal"><b><span style="font-size:7.5pt;font-family:"Arial","sans-serif";color:gray;mso-fareast-language:DE-AT">FDS</span></b><span style="font-size:7.5pt;font-family:"Arial","sans-serif";color:gray;mso-fareast-language:DE-AT"> | Forensik Data
Services.</span><span style="font-size:10.0pt;font-family:"Arial","sans-serif";mso-fareast-language:DE-AT"><o:p></o:p></span></p>
<p class="MsoNormal"><i><span lang="DE-AT" style="font-size:7.5pt;font-family:"Arial","sans-serif";color:teal;mso-fareast-language:DE-AT">Better secure than sorry!</span></i><span lang="DE-AT" style="font-size:10.0pt;font-family:"Arial","sans-serif";mso-fareast-language:DE-AT"><o:p></o:p></span></p>
<p class="MsoNormal"><span lang="DE-AT" style="font-size:10.0pt;font-family:"Arial","sans-serif";mso-fareast-language:DE-AT"> <o:p></o:p></span></p>
<p class="MsoNormal"><span lang="DE-AT" style="font-size:7.5pt;font-family:"Arial","sans-serif";color:gray;mso-fareast-language:DE-AT">Schenkelbachweg 32. A - 4600 W e l s.<br>
tel. 07242. 777 15. fax. 07242. 777 16.<br>
</span><span lang="DE-AT" style="font-size:10.0pt;font-family:"Arial","sans-serif";mso-fareast-language:DE-AT"><a href="mailto:office@fds.at"><span style="font-size:7.5pt;color:gray">mailto:office@fds.at</span></a><o:p></o:p></span></p>
<p class="MsoNormal"><span lang="DE-AT"><o:p> </o:p></span></p>
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