Am 01.10.2015 um 04:59 schrieb Grzegorz Powiedziuk: > I think I might have found a small bug in latest update for SLES12 so this > is just a FYI for everyone who made the same mistake I did. > > If you use edevices, you know that the FBA driver in linux automagically > (like Mark explained it to me few years ago ;) ) creates a device “1” > (dasda1 for example) on edevice. > You end up with for example dasda + dasda1 and you use dasda1 for OS > (including LVM) . No fdisks, no fdasds. > > I haven’t used edevices in a while so I forgot about that and my recent > SLES12 install I did on “dasda” (fba) , instead of “dasda1”. I don’t know > how I did that but I did it and SLES install wizard didn’t complain. System > installed fine and it is was working ok. > > pvscan on a build like this returned: > Volume Groups with the clustered attribute will be inaccessible. > PV /dev/dasda VG root lvm2 [19.53 GiB / 0 free] > > while in proper installation it looks like this: > > PV /dev/dasda1 VG lnx15 lvm2 [19.53 GiB / 0 free] > Total: 1 [19.53 GiB] / in use: 1 [19.53 GiB] / in no VG: 0 [0 ] > > > Everything was working fine, until I did an update. Something has changed in > the way LVM recognizes physical devices and it totally brakes the whole > system. It breaks all the parts where LVM is being called which includes the > little initrd which is loaded by zipl during the first stage of boot. > > I did some debugging and I found that with latest update of SLES (I don’t > know why because the LVM seems to be in the same version) lvm doesn’t like > having metadata on “dasda” (fba) anymore. It likes it only if its on dasda1 > When pvscan scans the disk it ends up with: > /dev/dasda: Skipping: Partition table signature found > so it does not find the label and it fails to bring online the pv and volume > group. > > This edevice, if linked to an original SLES12 or any RHEL is working fine. > LVM finds a label on /dev/dasdb (fba) and I can mount it without a problem. > > I didn’t find anything different in lvm.conf which could cause this. > > To fix this (well it’s rather a dirty hack), I’ve downloaded a sourcecode of > LVM, found the instruction where it exits on message "Skipping: Partition > table signature found” , commented out that section, compiled, installed this > lvm, rebuilt initrds (both of them) and it worked. I got my system running > again. > > So the lesson is to make sure that SLES is being installed on dasda1 (fba) > not dasda (only if you have edevices - with standard ECKDs it’s probably > ok to do that) > > If you already have it on dasda (FBA) - don’t update it without > preparations. > > Perhaps SLES shouldn’t allow to install a system this way at all?
Just guessing. Maybe this is a safety net to prevent the user from creating a physical volume on an ECKD dasd without partition. For this case not going onto a partion is indeed wrong. But doing so on an EDEV is certainly fine, so maybe its just the check that is too unspecific. Christian ---------------------------------------------------------------------- For LINUX-390 subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO LINUX-390 or visit http://www.marist.edu/htbin/wlvindex?LINUX-390 ---------------------------------------------------------------------- For more information on Linux on System z, visit http://wiki.linuxvm.org/
