On 03/01/2012 09:50 AM, Offer Baruch wrote:
I am using the /etc/sysconfig/mkinitrd/modules file to specify the zfcp module... But i did not run zipl as i only replaced the initrd. I thought that zipl should only run if you change zipl.conf. I tried to run zipl and the old luns are gone...
You were lucky you could even reboot with having the initrd updated but not run zipl. Actually zipl still booted the old initrd whose sectors were still on disk but already freed by the filesystem on generating the new initrd (the latter created a new initrd file and did an unlink on the old initrd). During time or on disk space pressure, old freed sectors will be overwritten and your old initrd content will be destroyed. Once that has happened you could no longer boot.
Please can you explain what zipl does with the initrd file?
I'm certainly no zipl expert and my colleagues will hopefully correct me. Generally, for anything that is needed to boot -- and this include kernel, parm file, and initrd -- the actual current disk sectors where the file content can be found is figured out by zipl and written in a so-called bootmap. On IPL, zipl uses this boot map to find the file content because it does not understand the Linux file systems.
On intel grub only points to the initrd file. Why is there any difference?
Grub (on any platform it is ported to) does understand Linux filesystems and therefore does not need an updated bootmap each time the content or sector layout of file needed to boot changed on disk.
In that respect, zipl is more like lilo rather than grub. Steffen Linux on System z Development IBM Deutschland Research & Development GmbH Vorsitzende des Aufsichtsrats: Martina Koederitz Geschäftsführung: Dirk Wittkopp Sitz der Gesellschaft: Böblingen Registergericht: Amtsgericht Stuttgart, HRB 243294 ---------------------------------------------------------------------- For LINUX-390 subscribe / signoff / archive access instructions, send email to lists...@vm.marist.edu 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/
