Re: lvm question

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



On Thursday 12 April 2007, Ed Greshko wrote:
>Gene,
>
>> So I started a dd if=/dev/hda of=/dev/hdd which cloned that 160GB drive to
>> a 200GB drive.
>
>AFAIK, when you dd in that manner, you are cloning as you say.  In that way,
>you are cloning everything.  By everything I mean you are cloning the disk
>label, partition table, inodes and all bad bits.  In effect, you've made a
>200GB drive into a 160GB drive.

Rant mode on here Ed.

Not permanently.  I was able to use fdisk and add a 4th partition to account 
for the rest of the drive after I was done.  That's why I asked the question 
about adding it to the LVM setup for real use, but no one has offered any how 
to on that, not yet anyway.

What I didn't understand was why it (/dev/hda3, the lvm volume) fsck'd on the 
first couple of boots after I'd made the the clone while I was fixing the 
partition table and usage on /dev/hdd to more or less match what was 
in /etc/fstab, since it dropped to a shell when it couldn't find the right 
stuff on the right partition of /dev/hdd.  There is no reason in the world 
that can explain why I couldn't edit /etc/fstab and comment that stuff out 
until I had a chance to get the main install fixed.  I even went so far as to 
edit the grub line from ro to rw and it made no difference at all.  But that 
was on /dev/hda1, which mounted just fine as rw so it was editable.

In short, I lost some hair trying to get around that when the stuff on hdb and 
hdd had absolutely NOTHING to do with a functioning, bootable system other 
that I'd forgotten to clean them out of /etc/fstab before I unmounted hdd, 
and cloned hda to it on a live system.

There was, and is, no valid excuse for that behaviour.  What was on /dev/hdd 
was only partitioned out of order.  That was accessory stuff that could have 
been fixed a hell of a lot easier from a booted, working system, but it 
turned into a cast iron bitch trying to do all that from a Zod livedvd boot.  
Even from the dvd boot, anything on /dev/hda3 was read-only without at that 
point, any errors being reported on screen by e2fsck, none, nada, zip.  They 
didn't show up until I got the partitions in a row on /dev/hdd and it booted 
past that only to upchuck over the lvm on hda3.  Then, and only then did it 
give me the correct command line to use to do an e2fsck on an lvm volume.  
The manpages on the dvd were worthless in that regard.  The e2fsck took 
around 5 hours, but I napped 2 of them maybe.  The real fix should have taken 
maybe 5 minutes, to correct /etc/fstab, but on a readonly disk, how the heck 
are you gonna do that?

FWIW, and probably a different reason, even though the livedvd had not mounted 
anything from /dev/hda, it still refused me write perms to do anything to it.  
Not parted, not fdisk, nothing.  Everything claimed the disk was busy.  To 
say that it was frustrating is an understatement of classic proportions.  
That is what forced me to run fdisk against a live, in use, drive.  But I 
didn't touch the existing partitions, only added another, 4th primary to 
account for the unused 40GB of that drive.

That should not have had any effect on the first 3 partitions, and in fact I 
have done exactly that previously, on a 30GB drive in an amiga.  I cloned a 
1GB seacrate to it, rebooted to it, and then added the other partitions I 
wanted.  The amiga, FWIW, did NOT limit the number of partitions per drive by 
any means other than running out of system memory since each mount took about 
64k to hold all the tables.  There was a reserved area of about 32k that 
could be expanded up to half a meg on an amiga-os formatted hard drive that 
could be used for all sorts of stuff, like a partition table with 10 or more 
entries, security passwords, custom boot files etc, and anything in there was 
invisible and not normally modifiable without getting out the disk tools.  
That was, IMO, one thing they did do right.

-- 
Cheers, Gene
"There are four boxes to be used in defense of liberty:
 soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
The Marines:
	The few, the proud, the not very bright.


[Index of Archives]     [Current Fedora Users]     [Fedora Desktop]     [Fedora SELinux]     [Yosemite News]     [Yosemite Photos]     [KDE Users]     [Fedora Tools]     [Fedora Docs]

  Powered by Linux