On Sat, May 26, 2007 at 09:50:41PM +0200, Pfenniger Daniel wrote: > Keith Lofstrom wrote: > >Thanks for SL5! > > > >I am currently upgrading two systems from SL44 to SL5 (the rest > >are getting fresh installs). > ... > >I do each upgrade on a "dd" copy of the original hard drive onto > >a spare; backing out of a failed upgrade is easier that way. > > The "wisdom" I have gathered is not to use dd for such > disk duplication, but to use fdisk for partitioning, and > "rsync -ax /orginal/ /target/" for file copy > (be careful with the trailing /'s). > > The first reason is that dd copies bad blocks, and > the second reason is that rsync over a blanck partition defrags the > files. A second rsync allows to check fast the first copy. The third > argument is that often disks are not strictly equal, and > then dd is anyway not recommended. > > Some use tar instead of rsync. I do this with two identical, modern drives, which seem to internally manage the bad blocks. The problem with rsync is that it sometimes does not copy metadata properly - even the mod dates for softlinks are not properly set. tar is less capable than rsync. Also, this way I get identical bits for the boot blocks. Otherwise I need to fool around with grub. I can do the copy in about 5 minutes of setup (mostly booting to single user and doing a sync first), two lines of typing, followed by a copy time of one hour per 150GB or so. The rsync approach involves a lot more setup and fiddling, even with automated scripts. Indeed, I used rsync and the automated approach to merge partitions. I missed a few things, and had to do it a couple of times to remember to find every bit of data, and to exclude things like /sys and /dev and /proc and /media (and of course the target drive) . Either way, it is important to use identical drive models. There should be identical spare drives anyway, because someday you will need to restore a backup to one, and that should be practiced beforehand. Keith -- Keith Lofstrom [log in to unmask] Voice (503)-520-1993 KLIC --- Keith Lofstrom Integrated Circuits --- "Your Ideas in Silicon" Design Contracting in Bipolar and CMOS - Analog, Digital, and Scan ICs