On Monday 31 January 2005 07:35, Paul Howarth wrote: > Robert Storey wrote: > > What's confusing to me here is that, in Fedora, I can't figure out which > > partition is mounted where. Is my / partition /dev/hda3, or /dev/hda5, > > or ??? Ditto for swap, or any other partition. If I wanted to make > > some change in the partition table (for example, adding a /home > > partition) I have no idea how I could get /etc/fstab to recognize it. > > > > I've tried making some sense out of fstab-sync, but so far it's pretty > > opague. Where does Fedora store the partition information? Anybody know > > some links that can explain this messy filesystem table? > > If you just run the command "mount" (you don't have to be root), you'll > see which partitions are mounted where. You can use either hardcoded > partition names such as "/dev/hda7" or filesystem label references such > as "LABEL=/home" in /etc/fstab; either will work OK. You can assign a > label to a partition when you create the filesystem on it by using the > -L option in mke2fs, and you can set or change the label of an existing > partition using the -L option in tune2fs. > or display and change labels with e2label But why label in the first place? I wondered about that for a while and came to this conclusion: If a drive in an Intel-like box is changed from master to slave or primary IDE channel to secondary or some other combination then the device name changes, e.g., /dev/hda1 to /dev/hdb1. When booting after this change without fixing /etc/fstab, mount cannot find /dev/hda1 because of its new location at /dev/hdb1. By labeling partitions and using the labels in /etc/fstab, mount will search all available partitions for the one with the name specified in /etc/fstab (or mount command). This eliminates the problem of device names changing when modifying the drive configuration. Labeling does introduce a problem: What happens if 2 partitions have the same label? Which one does mount choose? I do not know the algorithm but I do know that mount does not know which one you want to use. In the technical college where I taught Unix/Linux system administration we had removable IDE drives in our lab machines. (standard IDE drives in a tray that slides into a bay the in cabinet. works good. I use them at home too) I had a removable drive bay on my office machine. A couple of times I had to make some repairs to corrupted student drives. Since the drives are not hot-swappable I would power down my machine, insert the student's drive, power up and boot. Their partition labels were the same as on my internal IDE drive and as a result would bet mounted instead of my partitions. After a couple time of messing with that I changed the /etc/fstab file on my system to use device names instead of labels. fsck also recognizes the labels, probably other disk related commands too. paul -- Paul F. Almquist paul@xxxxxxxxxxxxx Eau Claire, WI USA
