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</o:shapelayout></xml><![endif]--></head><body lang=EN-US link=blue vlink=purple><div class=WordSection1><p class=MsoNormal style='text-align:left;direction:ltr;unicode-bidi:embed'><span style='color:#1F497D'>I just saw that clean_bits is being saved to the disk and is used to update sync_bits after crash/reboot (although the default behavior is to reset all the bits hence, resync is done for each resume).<o:p></o:p></span></p><p class=MsoNormal style='text-align:left;direction:ltr;unicode-bidi:embed'><span style='color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal style='text-align:left;direction:ltr;unicode-bidi:embed'><span style='color:#1F497D'>But I still do not understand how should I create a mapped device with dmsetup tool which wouldl survive crash/reboot.<o:p></o:p></span></p><p class=MsoNormal style='text-align:left;direction:ltr;unicode-bidi:embed'><span style='color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal style='text-align:left;direction:ltr;unicode-bidi:embed'><span style='color:#1F497D'>Can anyone help?<o:p></o:p></span></p><p class=MsoNormal style='text-align:left;direction:ltr;unicode-bidi:embed'><span style='color:#1F497D'><o:p> </o:p></span></p><div><div style='border:none;border-top:solid #B5C4DF 1.0pt;padding:3.0pt 0cm 0cm 0cm'><p class=MsoNormal style='text-align:left;direction:ltr;unicode-bidi:embed'><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"'> Eli Malul <br><b>Sent:</b> Sunday, March 20, 2011 6:19 PM<br><b>To:</b> 'dm-devel@redhat.com'<br><b>Subject:</b> the mirror log is NOT kept on disk<o:p></o:p></span></p></div></div><p class=MsoNormal style='text-align:left;direction:ltr;unicode-bidi:embed'><o:p> </o:p></p><p class=MsoNormal style='text-align:left;direction:ltr;unicode-bidi:embed'>Hi,<o:p></o:p></p><p class=MsoNormal style='text-align:left;direction:ltr;unicode-bidi:embed'><o:p> </o:p></p><p class=MsoNormal style='text-align:left;direction:ltr;unicode-bidi:embed'>I tried a small test where I suspended and resumed a mirrored device without IO going on.<o:p></o:p></p><p class=MsoNormal style='text-align:left;direction:ltr;unicode-bidi:embed'>My expectation was that the mirror set will not get re-synced but unfortunately it did.<o:p></o:p></p><p class=MsoNormal style='text-align:left;direction:ltr;unicode-bidi:embed'><o:p> </o:p></p><p class=MsoNormal style='text-align:left;direction:ltr;unicode-bidi:embed'>According the documentation the mirror log is kept on disk when creating a mirror logical device with 'disk' log type as an input parameter.<o:p></o:p></p><p class=MsoNormal style='text-align:left;direction:ltr;unicode-bidi:embed'>I looked at the code and I didn't see where the sync_bits are being written to the disk or read from the disk but only the number of regions is being saved.<o:p></o:p></p><p class=MsoNormal style='text-align:left;direction:ltr;unicode-bidi:embed'><o:p> </o:p></p><p class=MsoNormal style='text-align:left;direction:ltr;unicode-bidi:embed'>How should a mirror device survive reboots/crashes without syncing the entire mirror set?<o:p></o:p></p><p class=MsoNormal style='text-align:left;direction:ltr;unicode-bidi:embed'><o:p> </o:p></p><p class=MsoNormal style='text-align:left;direction:ltr;unicode-bidi:embed'>BTW – another problem is that after reboot the created logical device disappears, is there an easy way to keep it persistent or should I create at each boot?<o:p></o:p></p><p class=MsoNormal style='text-align:left;direction:ltr;unicode-bidi:embed'><o:p> </o:p></p></div></body></html>