Note: "permalinks" may not be as permanent as we would like,
direct links of old sources may well be a few messages off.
May be I should mount them read only. But I coundn't try agacin, since I've just flied back home I check the log file just now, and noticed that on secondary, md5sum report Input/ouput error, meanwhile the primary was ok. Does this mean I've mess up the metadata? On Fri, Aug 26, 2011 at 11:33 PM, Lyre <4179e1 at gmail.com> wrote: > Hi Lars: > > Yesterday, On the secondary, I shut down drbd, try to use rsync to > recovery the snapshot, but failed. Then I start drbd to resync from the > primary node. It was the only time I bypass drbd, howerver,the application > seems good at that time. > > This afternoon, we continue our experiment, disconnect drbd on secondary, > changed something and resync from priamry. Oracle was unable to start. drbd > status suggest that both node were uptodate, drbadm verify doesn't report > any error. Disconnect one side and mount drbd device on both node, md5sum > show that some files were different. > > > > On Fri, Aug 26, 2011 at 8:28 PM, Lars Ellenberg <lars.ellenberg at linbit.com > > wrote: > >> On Fri, Aug 26, 2011 at 05:50:59PM +0800, Lyre wrote: >> > Hi all: >> > >> > Is there a way to check the data integrity on both node? I've >> encounter >> > an confusing problem. >> > >> > We have two drbd devices, 20Gb one for application, and 300Gb one for >> oracle >> > database(oracle was installed in a different location, which were not >> > replicated), csums-alg & verify-alg were configured to crc32c, >> bandwidth >> > was 100M. >> >> I suggest to not use the same algorithm for csums-alg and verify-alg, >> so the verify can detect differences which the csums based resnc thought >> where identical due to identical checksums respective hash colision. >> >> I further suggest that you use stronger hash algorithms for both. >> Like md5 and sha1, or similar. >> >> > I try to upgrade our app & database on secondary(node2) , by disconnect >> and >> > promote 2 drbd devices to primary and then perform the upgrade, it was >> fine. >> > Then I try to roll back the seondary the original version, by drbdadm >> -- >> > --discard-my-data connect drbdX. After drbd sync, oracle was unable to >> > startup, it reports data corruption. So I issue drbdadm verify, but it >> > doesn't report anything, everything seems good. >> > >> > I disconnect drbds and then mount them on both side, md5sum all files on >> the >> > disk. I diff the output from both side and found that serval database >> file's >> > md5 value wasn't identical. Then I connect drbds and found that it begin >> to >> > sync about 30Gb's data. I didn't the device read only, but have all >> > applications stopped. >> > >> > >> > BTW, In earier, I've try to recovery the underlying lvm devices from >> > snapshot, but get IO error, so I just canceled and resync it. Does it >> > matter? Since I've get rid of drbd there. >> >> Can you give more detail there? >> What did you do? >> Did that manipulate DRBD meta data as well? >> Did you bypass DRBD at some point during the process? >> >> >> -- >> : Lars Ellenberg >> : LINBIT | Your Way to High Availability >> : DRBD/HA support and consulting http://www.linbit.com >> >> DRBD® and LINBIT® are registered trademarks of LINBIT, Austria. >> __ >> please don't Cc me, but send to list -- I'm subscribed >> _______________________________________________ >> drbd-user mailing list >> drbd-user at lists.linbit.com >> http://lists.linbit.com/mailman/listinfo/drbd-user >> > > -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.linbit.com/pipermail/drbd-user/attachments/20110826/13dbb691/attachment.htm>