Moving from 10.04 to 12.04

[Liam Proven]

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.

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.

-- 
Liam Proven • Profile: http://lproven.livejournal.com/profile
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