Moving from 10.04 to 12.04

[Jim Byrnes]

On 09/09/2012 09:50 AM, Liam Proven wrote:
> On 9 September 2012 15:15, Jim Byrnes <jf_byrnes at comcast.net> wrote:
>> On 09/09/2012 08:13 AM, Liam Proven wrote:
>>>
>>> On 8 September 2012 20:05, Jim Byrnes <jf_byrnes at comcast.net> wrote:
>>>>
>>>> Sooner or later I will need to move to 12.04.  Before I make the move I
>>>> need
>>>> to decide a couple of things.
>>>>
>>>> First should I upgrade or do a clean install.  When I went from Karmac to
>>>> Lucid I did an upgrade.  It seemed to work well and I have had no
>>>> problems,
>>>> but I see a lot of people advocating a clean install.  Looking at my home
>>>> directory I see it has become a jumbled mess so doing a clean install
>>>> would
>>>> give me a chance to restore some order.
>>>
>>>
>>> The upgrade will probably work fine, but f you can spare the time &
>>> effort to do a clean install, the result will be smaller, faster &
>>> probably more stable.
>>>
>>> Running 2 side-by-side is fine and safe and if you wish you can use a
>>> single swap partition shared between multiple installations - this is
>>> perfectly fine.
>>>
>>>> Thinking about doing the clean install I came up with this idea.  I have
>>>> a
>>>> brand new spare HD.  I could put it in my case, unhook the old one and
>>>> hookup the new one.  Install 12.04, get it running and install what I
>>>> need.
>>>> Then hookup the old HD and copy home and what ever else I find I need to
>>>> my
>>>> laptop.  Hookup the new HD and copy over what I need from my laptop.
>>>> This
>>>> way I have an untouched copy of 10.04 to use until I get 12.04 setup and
>>>> running the way I want it.  Does that make sense?
>>>
>>>
>>> Yes, that's fine. Unlike Windows, which can get confused and use
>>> resources from an old installation in a new one, *buntu is smart
>>> enough not to muddle them up. You don't need to disconnect your old
>>> HD.
>>
>>
>> Wouldn't there be confusion if there were two bootable HDs in the system?
>
> No. The bootloader will only be on the first.
>
> There will be /more/ trouble if you /do/ disconnect the old drive &
> reconnect it later, as then, there /will/ be 2 drives with a
> bootloader in their MBR.
>
> Also, unlike on PATA (EIDE) drives, with SATA, determining which is
> the "first" and which the "second" drive is a bit of a theoretical
> exercise; they are all peers.
>
> There is a notional order in terms of the numbering of the connectors
> on the motherboard, but this can be overridden in the BIOS so it's not
> much help.
>
> I'd definitely leave both connected.

I know from reading your posts in the past you know way more than I do, 
but I don't agree here.  Maybe I didn't make my intent clear.  The two 
drives will /never/ be hooked up at the same time.  The old HD will only 
be a fallback if for some reason I can't get everything working on the 
new install.

> Also, if you have the root FS on one drive and /home on a second, that
> gives a slight performance improvement. (Traditionally, it was best
> practice to put swap on a different physical disk from root, but as
> modern machines have gigs of RAM and don't really use swap much at
> all, this no longer offers much benefit.)
>
>> Or
>> would GRUB be modified on the fly to handle them?
>
> GRUB will only be installed on the first disk. It will be controlled
> by the most recent Linux to be installed.
>
>>>> This time I want to try a separate /home partition. I'm trying to decide
>>>> how
>>>> much space to give / and how much to /home.  The new HD is a 1TB one, I
>>>> will
>>>> probably only format about 300GB. My current HD is 500GB and I formatted
>>>> about 290GB and have 146GB free.
>>>
>>>
>>> Out of curiosity, what's the rest of the space for? Windows?
>>
>>
>> No, its just space I don't need so I didn't format it.
>
> Er, OK. Seems weird to me, but whatever turns you on.
>
>>   Also wouldn't
>> Ubuntu's periodic checking of the disk and maybe any repairs go faster with
>> less tracks formatted?
>
> No.
>
>>> Anyway, in terms of partitioning.
>>>
>>> You only really need 3:
>>> / - also known as "the root filesystem"
>>> /home - AKA "the home filesystem"
>>> swap - which doesn't get mounted, as such, so does not have a path
>>>
>>> All the software goes in the root FS. All your data goes in /home.
>>>
>>> These days, data is typically much bigger than S/W. Photos take many
>>> hundreds of meg, ditto music; videos take gigs.
>>>
>>> You don't usually need a lot of room for S/W.
>>>
>>> I would say that 8GB is a stingy amount of space but would probably
>>> work fine. 16GB is generous. 32GB is madly generous. More, for most
>>> people, would be wasteful.
>>>
>>> Swap, as you say, is typically 2× RAM (this is an old & now
>>> over-generous rule of thumb & is almost profligate these days, but
>>> hey, with a thousand gig to play with, why not?)
>>>
>>> All the rest can go to home.
>>>
>>> I always do it in a very old-fashion, standard way, using binary round
>>> numbers (i.e. powers of 2), like this:
>>>
>>> [ small optional DOS-bootable primary for BIOS flashing etc. - say
>>> 32MB, yes, *mega*bytes]
>>> [ bootable primary root - say 32GB]
>>> [ extended partition for whole rest of disk; in there: [/home] [swap] ]
>>>
>>>> I googled trying trying to find some guidance on how to allocate the
>>>> available space between / and /home, but found widely varying
>>>> suggestions.
>>>> I decided to look at what I was using on my setup now
>>>>
>>>> $ sudo du -shc /   =>  total 105G
>>>>
>>>> $ du -shc /home    =>  total 64G
>>>
>>>
>>> Just use GParted. Much easier.
>>
>>
>> Doesn't GParted just show partitions?
>
> It also shows space used in them.
>
>> Right now I don't have a separate
>> /home which is why I am trying to figure out how space I would need in / on
>> my system right now if I had a separate /home partition.
>
> OK. Well, I've already covered this.
>
>
>>> I suggest you give descriptive labels to your existing partitions.
>>> Gparted will do this & it is safe & non-destructive. Mine are called
>>> things like:
>>> "MS-DOS 32MB"
>>> "Spare primary"
>>> "Spare Ubuntu root"
>>> "Win2K 16GB"
>>> "Win7 24GB"
>>> "Home"
>>> "DATA 52GB"
>>> "2GB SWAP"
>>>
>>>> So this tells me that if I had a separate / and /home, / would be 41G.
>>>> 41GB
>>>> seems large compared to sizes I saw when I doing my search and many of
>>>> those
>>>> authors said they installed "tons of stuff".  So is the method I used to
>>>> calculate my current / size valid?
>>>
>>>
>>> 41GB is a lot but not madly so on a 1TB drive. It's only 4% of the space.
>>
>> Reading back over what I wrote maybe I wasn't clear.
>
> No, it's more that I am a little hungover. :¬)
>
>> Right now I only have
>> one big partition (disregarding swap).  I am trying to determine how big of
>> / partition I need just to accommodate the  S/W I have now. To do this I
>> took the size of / and subtracted the size of home. This gave me a size of
>> 41GB which seemed large so I am wondering if the method I used is valid.
>
> There are probably tons of caches and things in there which aren't
> needed and will be purged if you run short of space.
>
> E.g. the APT package cache is often huge. To see how big, try this:
>
> df -h ← to see how much free you have now
>
> sudo apt-get clean
>
> df -h ← you should see a big improvement
>
> sudo apt-get autoclean
>
> df -h ← small change this time
>
> sudo apt-get autoremove
>
> df -h ← again, not much change
>
> sudo apt-get purge
>
> df -h  ← again, little difference
>
> Also, look up your kernel version:
>
> uname -a
>
> E.g. 2.6.35 or something, followed by a hyphen & a build number, e.g. 2.6.35-22
>
>
> Now go into Synaptic & search for that version number, *without* the
> build number, e.g. 2.6.35
>
> Click on the "status" column to sort the ones that are installed at
> the top. (It's the first one, headed "S".)
>
> You will probably see 2 things.
>
> #1 - each kernel comes in 2 or 3 bits, "linux headers" and "linux image".
>
> #2 - that you have loads of old kernels still there
>
> You can safely remove all but the latest one. Highlight both parts of
> each old version - hold down Control to select multiple items - then
> right-click them and pick "mark for removal".
>
> Then click Apply.
>
> That will free up 100-200MB per kernel version with absolutely no
> adverse effects.
>
>>>> If it was valid I am thinking of a / of ~100GB and /home of ~200GB, does
>>>> that seem OK?
>>>
>>> 100 gig is /way/ over the top. I see no reason for more than 32GB max.
>>>
>> But my calculation tells me it is already 41GB which is why I am wondering
>> if my calculation is correct.
>
> Caches, old config files, source files, log files & various other
> cruft that builds up over the years.
>
> Happily on Linux it has little impact on performance, unlike in
> Windows. Linux is also very diligent about cleaning up its Temp
> folder(s) & rarely leaves old stuff there, whereas most Windows boxes
> have gigabytes of crap in there.
>

So are you saying here that my calculation method is correct, but I 
could reclaim a lot of space by doing what you outline above. In that 
case I should do the clean up and then redo the calculation.

Regards,  Jim