Thanks, this is what I suspected. Perhaps it won't surprise you to learn that the reason I was looking so closely at this setup is because that filesystem went catastrophically belly-up. The fsck took just shy of a week, with over 200,000 files in lost+found and not a single one in the regular directory structure.
Incidentally, RedHat's docs also say the /dev/dm* devices are for internal use only. Not sure why, but there you have it. I guess /dev/mapper/* is really what they want you to use. Also, here's a learning experience I'm taking away from this: when you verify that you have a good backup, be sure to inform the storage team that you would like them to extend the retention time on that data. Otherwise, if your fsck takes a week, you might find that they have overwritten your full backup in the meantime. On Wed, Sep 14, 2011 at 6:54 PM, Damion Alexander <[email protected]> wrote: > ----- Original Message ----- >> Here is my brain-teaser of the day. I'm wondering if somebody can >> help me figure out how this works and why somebody would set things >> up >> this way. It's possible that I'm just confused, too. >> > > It looks like someone misconfigured it to me. Probably assumed they named sda > as groundwork and sde groundworkp1, while not fully understanding > multipathing. I'm just guessing but it would seem like things written to > vgnagios will work fine if it only writes data to the first PV underneath. > But as soon as it writes to the "second" PV, /dev/mapper/groundworkp1, it > will start hosing data already written on the "first". > > I forget which path /dev/m* path I used to use, but I remember using the name > that multipath gave it during setup such as dm-0 in fstab. > > LVM probably only looks at the UUID of the device you give it to give it's > blessing and doesn't care about particulars. So since the partition has a > different UUID than the drive itself, LVM thinks everything is dandy. > > Damion > > > > _______________________________________________ > Tech mailing list > [email protected] > https://lists.lopsa.org/cgi-bin/mailman/listinfo/tech > This list provided by the League of Professional System Administrators > http://lopsa.org/ > _______________________________________________ Tech mailing list [email protected] https://lists.lopsa.org/cgi-bin/mailman/listinfo/tech This list provided by the League of Professional System Administrators http://lopsa.org/
