On Tuesday January 30, davidshine@xxxxxxxxx wrote: > Hi there, > > I am currenlty building a site ysing the following > > 2 * IBM DS4300 (SANS) > 2 * IBM X346 (intel systems) > 2 * HBA on each node > > I am using the md device driver to tie the two SANS together and use them in a mirrored environement. So the layout is 3 file systems sitting under and LVM volume group siting under a mirrored SAN (/dev/sdb, /dev/sdc) on 2 g.b. fibre using md driver. > > The problem when we write to one of the SANS when he mirror is > broken and then take this offline and ring the other SAN online and > switch on the RAID array and varyon the volume group and finally > mount the file system and then dismount the file system,swithc of > both the volume group and the RAID array and thn reboot the server > it finds the most recently updated disk to be the one written to not > the one last mounted. It's not really clear to me what you are trying to do here.... maybe if you explain your motivations and expectations. > > How does this work? Where is the date and time stamp written. I > thought it would be at the point of doing a aidstart and the supper > block would be updated, can you confirm this please? There is a timestamp on superblock but it isn't used much. The 'event count' is used more. So if you have a mirrored pair and : - stop it - restart with just one device - do some stuff, and stop it - restart with just the other device, do some stuff, and stop - reassemble the pair then the 'primary' could easily be either of the two, depending on which got the most event updates. Just don't do this. Again: what do you really want to do? NeilBrown - To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
