sd, sd, who's got the sd - f7 work required before release!

[David Timms]

Will Woods wrote:
> Styma, Robert E (Robert) wrote:
...
>> How will the two FC7 systems detect the new drive?
>>
>> Is there a method to the madness?
> 
> This is why we use disk labels or UUIDs instead of device names. With 
> changes like this in the kernel and especially with machines with 
> removable drives, or machines using fancy multipath storage, it's nearly 
> impossible to reliably predict exactly what order the drives will be 
> found in.
> 
> So the solution is: just give the partitions names instead. Then it 
> doesn't matter if your FC6 root drive is sda1 or sdb1 or hdc1, it's 
> always LABEL=fc6_root. If you say "mount LABEL=fc6_root /fc6" it will Do 
> The Right Thing.
> 
> So, in short, it doesn't matter how the two FC7 systems will detect the 
> new drive, so long as you give it a useful label.
Will, you could have mentioned:
1. a command to set the label ?
2. whether an lvm label like LogVol01 or LogVolhome is the same as the 
label you are mentioning ?

Consider it either good or bad that a long time redhat/fedora user does 
not know such a command - it gets set by the installer - for actual 
partitions, but not? for LVM logical volumes ?

After much searching "label lvm partition" etc in google with little 
result, I stumbled across the mkfs.ext3 parameter -L volume-label, but 
decided that would actually format the partition.

It seems that the required incantation is e2label:
# e2label /dev/sda6
to check, and add the new name to set it.

As some rh people have noted, it is almost impossible to automatically 
determine the mapping when booted with the f7 kernels / installer.

* So at the very least we need documentation that this is going to be 
the case and how to actually do it:
- on the popular fedoraproject wiki and fedorasolved sites. Currently no 
hits on either site. FedoraForum has a few mentions of e2label.
- actually in anaconda - at the point where anaconda decided "you need 
to label the filesystem"; otherwise this message is practically useless
   + tell the user to boot the existing system and run the pre-install 
check - next item

* a pre-install check tool for upgraders:
   + python script / executable on the cd/dvd install media root dir
   + ? set for autorun ?
   + "would you like to run the fedora 7 pre-install check ?"
   + check that all mounted partitions have labels {or whatever it is 
exactly that the installer needs to get around the /dev/hdX /dev/sdX 
changes.}
   + if "not happy"
     - offer to set any missing labels based mtab/fstab/fdisk info and 
current mount points from the running system.
     else
     - "the partition labeling required to ease the upgrade to f7 are 
present. you are ready to reboot the installer to begin the upgrade"

* fdisk needs to show the partition labels {future} - since it is going 
to be relied on so much

* lvm ?
   - is an lvm label the same as a partition label ?
   - if not can it be used in the same way ?

* need to be able to set the labels in anaconda partitioning - currently 
you can set the mount point - but not the label.

DaveT.