Question replacing a hard drive on 9.1

[banjo]

I currently have a disk situation which I am trying to

solve. The problem is that my 40Gig disk is making a

noise when it spins up, so I have procured a new

disk that is 120G to replace it. So far, so good.

 

 

Mandrake partitioned my 40G disk at install time

in the following manner:

 

Size Used Avail Use% Mounted on

part1 /dev/hda1 5.8G 3.6G 2.0G 65% /

part2 extended partition

part5 /dev/hda5 swap 494 Meg

part6 /dev/hda6 31G 1.9G 29G 7% /home

 

This is on a home system used primarily for the

usual email and browsing functions.

So this works fine for me, except that the root

partition is getting a bit full, and my son wants

to install some large games later.

 

 

What I want to do is to partition my new disk

in a more friendly fashion, giving more room to

root for these large installs. Then I will copy the

contents of the old disk to the new one and make it

bootable. I have studied lots of tutorials on how to do

this, but I still have some questions for which

I have not found answers. So I thought that I would

post them on this board.

 

I am thinking of partitioning the new disk in

the following manner:

 

part1 /dev/hda1 500Meg /boot

part2 extended partition

part5 /dev/hda5 swap 500 Meg

part6 /dev/hda6 119G /

 

By putting all of root (including /home) on

one partition, I avoid the unanswerable question,

"How big do I make root to avoid running out of space

and yet avoid wasting space I could have used on /home?"

Basically, most of the disk would be a single partition

similiar to (oh GAG!) fnWindows. The root directory can

then use as much space as it needs.

 

The reason for the small /boot partition is that I read

somewhere that the bootable partition cannot be larger

than about 8Gig to make it all adressable by the BIOS.

That might not be big enough for the memory hogging games.

Hence, it is just /boot, not root.

 

Here are my questions:

 

1). Is it still true that the bootable partition

must be less than 8 Gig? I have a new Intel 2 GHz motherboard

procured last May. I understand that the size limit

is a BIOS limitation. Can I simply partition the

disk as the old one is now and just make a large,

say 40G, root partition? If I do it that way, I should

not have to change the config files.

 

2). Is there an overpowering reason for having /home

on its own partition, separate from / ?

 

I see nothing but negatives from having to guess how

much space to give the root partition instead of simply

letting it have whatever it needs of the disk.

 

I do not do system backups of partitions, being of the mindset

that it is quicker and easier to reinstall the system

on a new hard disk than it is to do hours and hours of

system backups over the life of the disk just to save a

couple of hours to reinstall. User files are backed

up separately. Am I messing up if I put root and /home

on the same partition?

 

 

3). When I partition the new disk, what do I name the

partitions?

 

I will partition the new disk installed as /dev/hdb

and then copy the directories from /dev/hda to /dev/hdb,

then install the new disk as /dev/hda, run lilo and

reboot.

 

/proc/partitions shows the partitions as part1, part2, part5, and part6.

HardDrake shows them as devices hda1, hda5, and hda6.

Do the partition names matter?

 

I assume that the new disk partitions will be mapped to /dev/hdaX

by the BIOS regardless of partition names when I install the

new disk as IDE0 master? Is this correct?

 

Thanks in advance for your help. If I get this to

work I will publish what I did on the board.

 

Banjo

(_)=='=~

[kfoss]

1. I used to have a 30GB partition which held everything, so the 8GB limit is likely not a limitation, though there may be limitations within your BIOS.

 

2. A clue to the answer to this question is the second word in my first response. I used to have it on an all-in-one partition. However, when I had problems with the OS or wanted to upgrade, I would lose all my 'home' data. It isn't usually a problem however I lost all of the backup files my wife was saving on her home directory and a bunch of digital pics. I like having 'home' on a separate partition and even better on a separate drive.

 

3. For the names, you really don't have much choice. The /dev/hdX names are based on where the drive is on the IDE bus and the types of partitions. Primary partitions are normally numbered as /dev/hda1 for example and extended partitions normally start above 5, such as /dev/hda5. So you'll need to set up your partitions in the same manner as the original install, with your new sizes of course.

 

In general, I've tried to avoid this type of transition. I've been more successful with a complete reinstall on the new drive. Then with the old drive as a secondary, I slowly transfer specific config and data files, such as samba, network scripts, home directory, desktop configs, etc. Eventually I have the whole system set up, but at any one time I can always put the old drive into the primary position and have my old setup running in a minute.

[roland]

Hi,

 

Having / and /home on the same partition is not a good idea imho.

Mandrake does not upgrade well so far (as any other distro except debian AFAIK)

So when you want to change your distro's version you have to do a clean install so erase the / partition. Then what about your data if your /home in in / ? erased.

I can be wrong and be corrected but it seems to me that a 10 to 20 Gb partition will be enough for a while for /.

So better install your new Hd as hda, install your old Hd as hd<else>, do a fresh install on hda with a 10-20 Go / partition, keep your /home on hd<else> for now.

Once completed, if you want to move your /home on your new Hd (hda), better let DiskDrake do the job: create a /home partition on hda, DiskDrake will say that you already have a /home elsewhere and will propose to move it to the new place.

That's the easiest way imho

 

roland

[banjo]

Thanks for the feedback.

 

It was making me nervous to put root and /home on the same

partition, but I wasn't sure why. I suppose that if it ever became

necessary to wipe the / partition it could get ugly.

 

I did not want to re-install on the new disk in order to avoid

having to reconfigure all the apps. But that may be the

quickest thing to do after all.

 

I will go do some more research before jumping in.

 

Thanks again.

 

Banjo

(_)=='=~

[roland]

I did not want to re-install on the new disk in order to avoid

having to reconfigure all the apps.

As your old /etc is still there it must not be too difficult.

 

roland

[kfoss]

I share your fear of having to reinstall all the apps. I use my system for many tasks but a prime use is multimedia/video. It is a pain to get all the apps such as MPlayer and Transcode working the way I want them and then have to reinstall and go through it all over. I've learned to take notes during my installs as to what I installed and for what reason, ie. to satisfy what dependancy...

 

If you follow the recommendations on this topic, you should be fine.

[banjo]

OK. Here is another crazy idea I had.

We used to link /tmp to /home/tmp when root

was too small for the huge temp files we were

creating. It worked great.

 

Suppose that I did a smallish (say, 8 Gig) root

partition as the first primary partition and then,

once I get it going I could link /usr and /var to

/home/var to get more space (copying current

contents over, of course).

 

Has anybody ever tried to skirt the size issue

doing something like that?

 

Banjo

(_)=='=~

[kfoss]

I tried that exact same method. In general it works, and I've done the same for my /usr as I find it grows much quicker than any other major directory.

 

However, there are some disadvantages. I had the HDD on which the /tmp was linked die. Unfortunately, the OS needs a /tmp directory to do basically all tasks. Without it, I was blocked from booting until I used a rescue disk to change the /etc/fstab and point /tmp to a working location.

[banjo]

That makes sense. But I wasn't thinking of mounting it

on a different disk. I was thinking of just creating

a symbolic link of /usr to /home/usr. That should

leave the original /usr intact but unused. If I copied

all of /usr over to /home/usr before creating the link

the system should not see any difference on reboot.

 

 

Since all of my partitions will be on a single hdd,

if the hdd dies I am toast anyway.

 

I am assuming that the OS would not care that the

/usr was actually a link rather than a real directory.

Sometimes the low level stuff can treat a link in

a slightly different fashion.

 

Banjo

(_)=='=~

[kfoss]

Banjo...you're right. I never made that leap of logic which would have saved me some heartache.

[banjo]

Well, I am certainly learning a lot about how Linux

hangs together. This board is a great resource.

 

I have downloaded a copy of Linux-Filesystem-Hierarchy.pdf

and I am now studying it. When I figure this out and get

it done I will post my final answer on the board.

(Could be a while.... I am a slow reader... and my finger

gets tired). :D

 

One of the great things about Linux and Unix is

that there are many ways to get the job done. We

are limited only by our creativity.

 

Banjo

(_)=='=~

[roland]

Suppose that I did a smallish (say, 8 Gig) root

partition as the first primary partition and then,

once I get it going ...

 

that means 8 Gb is enough ...

 

... I could link /usr and /var to

/home/var to get more space (copying current

contents over, of course).

 

/tmp or /var, that makes sense imo but /usr, that may complicate your life if you do a fresh install in the future.

 

roland

[banjo]

The issue with the "small" 8 Gig root is that my son

wants to install some fairly greedy game programs

later. I have heard numbers as large as 3 Gig for a

program.... :o (remember when a 10 Meg drive

was huge?). Two or three of those things and my

"small" 8 Gig root partition is looking full.

 

So, the issue is not that I cannot get it working without

a huge root partition. The issue is that the root partition

may become huge later, and I don't want to run out of

space.

 

The reason I flagged /usr for a link to a larger space

is that I was under the impression that most of the

user apps are installed there. Perhaps I am wrong.

I still have some more studying to do about how the

file system is laid out. What I want to do is to link

the directories which are going to grow huge out to

a very large space.

 

Maybe I need to step back again and go back to

basics.

 

Does anybody know how I can find out if the

1024 cylinder limit on the boot sector is still an

issue?

 

I continue to ponder.

 

Banjo

(_)=='=~

[Cannonfodder]

Generally, the 1024 cylinder issue is no longer an issue.. not sure when it is.. maybe older systems or older linux kernals?

 

Just consider that if a partition fills up, as mentioned earlier, a directory link to a new partition can be created. You can look on your old system and determine where most of the space is being used. My root is only about 600 meg. Very small. Everything else is farmed out to new partitions.

 

Trick is to remember to make the entire drive and extended partition so you do not run into the maximum of four primary partitions.

 

Also, if you need to copy any partitions from one drive to another, hook em both up and use

 

cp -pax source dest

 

Have fun :)

[banjo]

Thanks for the info.

 

My MOBO is an Intel D845PESV which I bought in May of last year.

I will see if I can find out whether the old cylinder limit

is fixed in it. I want to be sure that I don't run into any problems

in the root directory, if you get my drift.

 

Mandrake set me up with a root partition of 5.8 Gig, and I have now

used about 3.6 Gig. Last night I did some du's and found out

that 3.3 Gig are used by /usr and about 0.3 Gig are used for

the rest of it.

 

So I thought that I might make a separate partition for

/usr and set it up as it is now for the rest of it

(with larger partitions, of course). That avoids the mystical

8 Gig limit on root and gets me all the space I need for /usr.

 

And yes, I plan on putting most of the partitions into a large

extended partition to avoid that yet-another-ridiculous-limit

of four partitions on a disk problem.

 

Funny story: Way back in the early '80's a friend of mine

was at a football game when a scrolling advertisement came

across the scoreboard. The bank ATM's were brand new then,

and the ad was something along the lines of:

 

"Baybank ATM's. Now serving 255 locations!"

 

My friend said that he started laughing so hard he

fell out of his seat. The folks around him could not

understand what was so funny.

 

We figured that some poor software weenie lost his

job that day............ or got promoted to Management.

 

Banjo

(_)=='=~