Messages in this thread | | | From | bsuparna@in ... | Date | Thu, 15 Mar 2001 17:51:36 +0530 | Subject | Re: (struct dentry *)->vfsmnt; |
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>Actually, I'm pretty sure you _never_ need to exportvg in order to have >it work on another system. That's one of the great things about AIX LVM, >because it means you can move a VG to another system after a hardware >problem, and not have any problems importing it (journaled fs also helps). >AFAIK, the only think exportvg does is remove VG information from the >ODM and /etc/filesystems. >
Yes that's correct as far as I know too. The VGDA and LVCB contain all the information required for import even without an exportvg.
>I suppose it is possible that because AIX is so tied into the ODM and >SMIT, that it updates the VGDA mountpoint info whenever a filesystem >mountpoint is changed, but this will _never_ work on Linux because of >different tools versions, distributions, etc. Also, it would mean on >AIX that anyone editing /etc/filesystems might have a broken system at >vgimport time (wouldn't be the first time that not using ODM/SMIT caused >such a problem).
Yes, you can think of crfs (or chfs) as a composite command that handles this (writing to LVCB. These are more like administrative/setup/configuration commands -- one time, or occasional system configuration changes.
On the other hand a mount doesn't cause a persistent configuration information change. You can issue a mount even if an entry doesn't exist in /etc/filesystems.
> >> ... I do think that the LVM is a reasonable place to store this kind of >> information. > >Yes, even though it would tie the user into using a specific version of >mount(), I suppose it is a better solution than storing it inside the >filesystem. It will work with non-ext2 filesystems, and it also allows >you to store more information than simply the mountpoint (e.g. mount >options, dump + fsck info, etc). In the end, I will probably just >save the whole /etc/fstab line into the LV header somewhere, and extract >it at importvg time (possibly with modifications for vgname and mountpoint). > >Cheers, Andreas
Is mount the right time to do this ? A mount happens on every boot of the system. And then, one can issue a mount by explicitly specifying all the parameters without having an entry in fstab. [Doesn't that also mean that you have a possibility of inconsistency even here ?]
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