<html><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; ">Hi, <div><br></div><div>I've done a little further testing and ran DRBD directly on top of the raid set (without using dm_crypt). Still got the same disk flush errors when having flushing enabled. </div><div><br></div><div>So can I assume that either the lower level scsi driver megaraid_sas (Debian 2.6.18.6-amd64) or the raid controller (LSI MegaRaid 1078) does not support flushing?</div><div><br></div><div><br></div><div>And another question: Can disabling flushing in DRBD cause any other problems than data corruptions at power loss?</div><div> </div><div><br><div><div>Am 15.12.2008 um 16:45 schrieb Thomas Reinhold:</div><br class="Apple-interchange-newline"><blockquote type="cite"><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><div><br></div><div><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; ">Thanks again. The driver module is sas_megaraid (I'm using Debian 2.6.18 dm-crypt, not RedHat).<div><br></div><div><div><div><br></div><div><div><div>Am 15.12.2008 um 15:35 schrieb Lars Ellenberg:</div><blockquote type="cite"><div>On Mon, Dec 15, 2008 at 03:14:28PM +0100, Thomas Reinhold wrote:<br><blockquote type="cite">Thanks for your quick answer. <br></blockquote><blockquote type="cite"><br></blockquote><blockquote type="cite">This is the complete error message (I shoud have posted that in the first<br></blockquote><blockquote type="cite">place, sorry):<br></blockquote><blockquote type="cite"><br></blockquote><blockquote type="cite"><br></blockquote><blockquote type="cite"> Dec 11 21:47:56 bftest-54 kernel: FAILED<br></blockquote><blockquote type="cite"> Dec 11 21:47:56 bftest-54 kernel: status = 1, message = 00, host = 0, driver = 08<br></blockquote><blockquote type="cite"> Dec 11 21:47:56 bftest-54 kernel: <6>sd: Current: sense key: Illegal Request<br></blockquote><blockquote type="cite"> Dec 11 21:47:56 bftest-54 kernel: Additional sense: Invalid command operation code<br></blockquote><br>well, that is from the scsi layer.<br>and yes, that is exactly the decoded scsi_execute_req return value<br>0x8000002 ;)<br><br><blockquote type="cite"> Dec 11 21:47:56 bftest-54 kernel: drbd0: local disk flush failed with<br></blockquote><blockquote type="cite"> status 134217730<br></blockquote><blockquote type="cite"><br></blockquote><blockquote type="cite">What I forgot to mention is that DRBD runs on top of a dm device (dm-crypt),<br></blockquote><blockquote type="cite">which in turn runs on top of the raid array. Could that cause the problem?<br></blockquote><br>I was not aware that redhat has patched its 2.6.18 dm-crypt to<br>(pretend to?) support flushed/barriers.<br><br>but that should be irrelevant in this context.<br><br>apparendly your lower level driver (what driver module is in use?) does<br>not support flush requests, or something in the device mapper stack<br>converts the flush request into something that the driver does not<br>understand.<br><br>we may consider to handle any return value != 0 in the same way in drbd.<br>meanwhile, the correct fix is:<br><br><blockquote type="cite"> I have disabled disk flushing for now, and the error obiously has gone.<br></blockquote><br>-- <br>: Lars Ellenberg<br>: LINBIT | Your Way to High Availability<br>: DRBD/HA support and consulting <a href="http://www.linbit.com/">http://www.linbit.com</a><br><br>DRBD® and LINBIT® are registered trademarks of LINBIT, Austria.<br>__<br>please don't Cc me, but send to list -- I'm subscribed<br>_______________________________________________<br>drbd-user mailing list<br><a href="mailto:drbd-user@lists.linbit.com">drbd-user@lists.linbit.com</a><br><a href="http://lists.linbit.com/mailman/listinfo/drbd-user">http://lists.linbit.com/mailman/listinfo/drbd-user</a><br></div><div><br></div></blockquote></div></div></div></div></div></div></div>_______________________________________________<br>drbd-user mailing list<br><a href="mailto:drbd-user@lists.linbit.com">drbd-user@lists.linbit.com</a><br><a href="http://lists.linbit.com/mailman/listinfo/drbd-user">http://lists.linbit.com/mailman/listinfo/drbd-user</a><br></blockquote></div><br></div></body></html>