Partitioning for a dual boot

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1

First of all sorry for the repeated thread i know there is a gazilion other threads and articles for this and i went through hundreds of them but I still couldn’t figure this out .
So the situation is this :
I have an acer aspire 5930g laptop with a 320Gb hard drive which is partitioned as follows http://img19.imageshack.us/img19/1886/capturemp8.jpg
the C partition holds a 32 bit win Vista home premium which may be replaced in the future with 32 bit vista business or 64 bit seven but that’s not relevant

So exactly how many partitions does opensuse 11.1 need ? and what is the recommended sizes (taking in mind that i want to save all my data in the D partition that already exists ) ?
and i probably will be installing a lot of games and applications .

And it’s my understanding that the data partition D cannot stay NTFS if i want to use it with opensuse and vista so what file system should i use ? and does transforming it delete all my preexisting data ?

and finally can g-parted do the job ? if not then what program should i use ?
and do i really need to backup everything cause I can but I really rather not to as i don’t have the means so i’d have to borrow a friend’s external hdd which would be backed up first to another friend’s computer ?

And i’ve read in many places that opensuse misses up the MBR (whatever that is) which makes you unable to boot into vista unless repaired by the original vista disc ? which i don’t have cause this is an OEM (though i do have a retail vista business DVD which i can upgrade to now then repair with when the **** hits the fan)

and i’ve also read that moving the vista partition with g-parted causes the same problem as previously mentioned is it true ?

oh and if I partitioned using a program before the actual install , when installing I should be able to direct the opensuse to the new partitions with no problem ?

sorry for the LONG post but i wanted to explain the situation thoroughly :dlol!

2

Basically, you need a minimum of three partitions:
/ which holds all your system files
swap
/home which holds your user files.

If you have the space, make / 20G but, unless you are going to add a lot of programs, 10G should be enough. swap is normally 1.5-2 times RAM but, if you have a lot of RAM, you may not need it to be very large. Some people just add 512 Mb of swap to a system with a lot of RAM to provide some overhead.

You can ask Vista to create the space on C: and D:, which some people advise and others regard as unnecessary. But, if you don’t, defrag both partitions first.

/home should be as much as you can spare.

If you install almost any distribution, it will have an expert/custom partition option which you will need as you are not going to have a standard setup.

If you use this within openSUSE, you must also mount your Vista partitions as part of the expert partitioning, something like /windows/C and /windows/D will do but, once you have done this, you can leave the installer to do the actual formatting of the space that Vista has made for you.

Accept the standard installation of GRUB which involves overwriting the MBR.

Accidents can always happen; so back-up before you do anything but normally openSUSE is well-behaved and will not mess anything up. I have certainly never had any problems with it messing things up.

3

So exactly how many partitions does opensuse 11.1 need ?

Two, one for the root system and another for swap. It’s also useful to have a third partition for the /home folder, that way you can, for example, install a new version of the OS without loosing most of your configuration.

and what is the recommended sizes (taking in mind that i want to save all my data in the D partition that already exists ) ?
and i probably will be installing a lot of games and applications

For a system with a separate /home partition I’d use about 20 GB. For swap use at least the same size as your memory if you pretend to suspend to disk. Lot’s of people use more (if they have small memory, say less than 512 MB) or less (if they have a lot of memory). Some even don’t use it. With 4GB RAM I’ve never seen the system monitor accuse swap usage. With 2GB and a virtual machine running it is rarely used.

And it’s my understanding that the data partition D cannot stay NTFS if i want to use it with opensuse and vista so what file system should i use ? and does transforming it delete all my preexisting data ?

Correct on both counts. Although you can have read-write access to NTFS partitions using the ntfs-3g filesystem drivers, it’s still strongly not recommended, as you may/will have problems when accessing it alternately (suse, then vista, then windows7, the suse, etc.) Opensuse currently defaults to ext3, which is stable and not too outdated.

and finally can g-parted do the job ? if not then what program should i use ?

A partition editor can create and format the partitions for you, but not set the bootloader and stuff. You can do that during opensuse installation (but the new partitioner, although very complete, is not too intuitive), If you prefer to set the partitions before installation I’d recommend a liveCD like PARTED MAGIC. There are others, as good or better.

and do i really need to backup everything

You should always backup data you need and can’t recreate easily. If you’ll reformat the NTFS partition that’s a given.

And i’ve read in many places that opensuse misses up the MBR (whatever that is) which makes you unable to boot into vista unless repaired by the original vista disc ?

I don’t think so, I believe it’s related to suse not setting your C: partition as primary and/or not writing the boot code to the primary partition. You can set this during installation, if you know what to look for. There is an excelent howto from sverdna at the stickies you can read. There are also a number of posts explaining how to do this.

and i’ve also read that moving the vista partition with g-parted causes the same problem as previously mentioned is it true ?

Possibly. I remember reading that vista monitors where it is installed, and complains if it’s moved (even if everything else works, may be an anti piracy thing)

oh and if I partitioned using a program before the actual install , when installing I should be able to direct the opensuse to the new partitions with no problem ?

Yes, easily. Just be sure not to mark the partitions for formating.

sorry for the LONG post but i wanted to explain the situation thoroughly :dlol!

You did, don’t worry :slight_smile:

4

@john_hudson

Sorry for the cross-posting, didn’t see you had already answered.

5

I will offer a few different perspectives . . .

First, there are known serious issues when altering Vista created partitions with any tool not “Vista certified” - and that includes many Windows tools like Partition Magic (before it was certified). The compatibility problems seldom arise, as there must be a combination of factors at work at the same time and sometimes in a particular sequence. In the case of one of these issues, it applies only to certain bios’s. As a result, usually there is not a problem using an XP tool or one of the linux parted-based tools (gparted, SuSE partitioner, etc.). But such problems do occur - even when the mix is only XP and Vista - and when they do, the consequences are typically quite serious. Vista has a partition management tool which supports on-the-fly resizing. It would be better to downsize D with Vista leaving unallocated space in which you would create an “extended” primary, in an amount equal to the sum of your Linux partitions, and then let the Linux install use that space to create the 3 Linux partitions as “logicals”.

However, before approaching that, you have another issue I don’t see being addressed. Your Vista partition report/graphic indicates there are already 4 primary partitions on the disk. There is the 9.77GB at the front, and a 3GB at the back. On an x86 machine, there can be no more than 4 primaries; the only way you can have more partitions is for one of the 4 primaries to be an “extended” primary which acts as a container to hold “logical” partitions (as ref’d my prev paragraph). Currently, if you downsized C or D you would not be able to use the space; the partition table is already full. Your only feasible options are to remove the 4th partition and downsize D, and then in the resulting free space create a new 4th primary as an extended. Or you could move the data that is on D to an enlarged C, then delete D and use that space for the new 4th extended primary. The key question is, what are the present 1st and 4th used for? If you created the 4th yourself, then you can use the first option above, i.e., replace it with a new extended primary after downsizing D. But if the 4th came setup on the machine from the factory, then it is highly likely that it is used for system recovery. The 1st partition is almost for sure the “recovery image”, i.e., the copy of the OS as it left the factory which gets copied back to C for recovery. The 4th partition may hold the recovery program itself, i.e., without it you may not be able to use Acer’s recovery mechanism. You need to sort this out before proceeding.

Finally, in ref to installing the boot loader. As others have mentioned, you will find differing opinions here - but many comments were made early in the experience curve with Vista, before info came trickling out about Vista’s different partitioning rules and Vista’s different use of the disk signature within the MBR, etc. The bottom line is, while it usually is fine to install grub to the MBR, in a non-trivial number of cases - primarily with laptops - there are difficult problems. The view of the dev’s, which I share, is that the safest approach is to leave the Windows code in the MBR untouched when possible. As it turns out, while this can be difficult to achieve with XP, it is very easy to do with Vista because Vista’s boot manager is significantly more powerful and flexible. The only issue is that the program Microsoft provides to configure the Vista boot manager is a very unfriendly command-line tool. However, there is a very popular and easy GUI tool called EasyBCD which will do the setup for you. All that is required is, when installing openSUSE, at the Boot Loader step to instruct that grub be installed to the openSUSE partition rather than to the MBR. Then in EasyBCD you simply add a menu entry pointing to that partition, reboot and Vista’s boot manager will present a menu with a choice to call grub from the openSUSE partition for booting Linux. You can read about/get EasyBCD here EasyBCD 1.7.2 - NeoSmart Technologies.

6

Thanks for the clarification. I am curious about two things that happened to me regarding this:

  1. I had some issues with the boot record not being in the MBR, I couldn’t boot after removing a temporary backup IDE drive (not a system one) from a machine with 11.1 and XP in dualboot. I got it working again, with sverdna’s help, after rewriting the boot code to the MBR of the main (SATA) disk using the installation DVD in repair mode, I think. I’m quite sure the boot code was not written to the temporary IDE drive originally, it was just a backup of the previous /home. So I got the impression that OS 11.1 installation defaulting not to write the boot code to the MBR made the system more vulnerable to hardware changes, although it worked the two or three days (and reboots) before I removed the drive.

  2. in an HP laptop with vista home basic I installed OS 11.0 (not 11.1) a few weeks after it came out, with the boot code in the mbr. Haven’t booted into vista for a long time, booted just now to make sure it’s working. Yast>System>Bootloader shows the 'boot from MBR selected, so I think 11.0 installed it the same way it does with XP.

Now, the laptop has a simple configuration, only one HD, no raid or mixed technologies (IDE, SATA, external drives), and as such maybe the problems you mentioned may not arise frequently. As I don’t use vista I dont care about it, but I’d be wary of using the default OS 11.1 boot scheme with XP. I don’t know if I’m off the track here.

7

There is no “default” boot loader configuration per se, other than using grub as the loader. The YaST Boot Loader module uses a program which looks at the partition table, the MBR code, the disk layout, the bios map, and the PBR (partition boot record) to try to determine the best setup. If the program finds a straightforward setup such as was common 5 yrs ago - for example, just a Windows C volume - it will install grub to the SuSE partition boot sector and mark that partition active; there is no reason to replace the MBR code. If the program finds two or even three Windows primary partitions, it may (depending on what else it finds) create a fourth as an extended primary with three logicals in it for openSUSE, and install grub to the extended primary boot sector; again, no need for replacing the MBR code. On the other hand, often the program will detect a characteristic in the system that absolutely requires grub to be installed to the MBR, or else multiboot will just not work.

There is a lot more involved here than the user can see. Bios’s are written by 3rd-party companies and are not extensively tested by machine manufacturers except in the factory configuration. Often there are flaws or inconsistencies in how bios’s handle anything other than booting from the first drive. For example, some bios’s permit the user to specify IDE boot disk sequence, but not for SATA drives. Some bios’s allow booting from USB; with one type of USB storage, if the device is not found the bios will fall back to the next configured device, but with another type of USB storage the bios will not fall back and instead locks up. There are many more such examples. There is no bios boot standard. The boot sequence configuration is not even in the bios hardware map, which is why grub must guess at boot time and why for installation grub depends upon device.map (and is why SuSE wrote the program above which considerably improves upon the guess).

In recent years this all has become much more problematic. Manufacturers began adding bios extensions and unusual, undocumented partition layouts (particularly in laptops) to support OS recovery; apparently some even modify contents of the MBR. On the OS side of the equation, Microsoft has expanded its use of the MBR disk signature and with Vista, introduced partitioning rules that can cause incompatibilities with other OS’s including earlier versions of Windows. Just this week installing W7 I found it using a FAT16 partition type in the table rather than NTFS; the OS didn’t care but it upset the linux partitioning tools. (There is one saving grace with Vista and W7, the new boot manager, which while unfriendly to configure, is quite flexible - and was specifically designed to handle most any multiboot, multi-OS, setup.)

About the only thing that can be counted on working 99% of the time is the original x86 boot setup - the presumption that the boot disk is the first bios disk, simple code in the MBR which scans the table for the first record with an active boot flag, finds that partition’s boot sector, transfers control to the jump instruction there. Grub stage1 typically works very well when installed in the PBR because when formatted with a linux file system it is entirely predictable; a file system driver (the grub stage1.5) is also installed in the PBR enabling it to find stage2. Grub works equally well installed in the MBR as long as there isn’t anything to get in its way; but unfortunately, as described above, sometimes that is not the case and it is very difficult to predict. The bottom line is if the present (or “generic”) MBR boot code works fine with grub in the PBR, then putting grub stage1 in the MBR adds no value whatsoever and unnecessarily adds risk; however, with currently commonplace disk layouts (again, especially laptops), there is often no choice but to put stage1 in the MBR.

I can’t comment on why you had the experience you did vis-a-vis the second IDE drive. What I can say is that any such experience should not be extrapolated into a conclusion about what should be a default; there are too many variables. The YaST Boot Loader program works down a complex decision tree to determine its installation suggestion. Sometimes looking at the entire MBR contents, will explain the unexpected boot behavior. But if the issue is some strangeness in the bios, which is most often the case, that’s virtually undetectable. A good read here http://en.opensuse.org/Bugs/grub - note the section “How can I set up a working grub?”.

8

Wow! Thanks Mingus, lots of good info here. :slight_smile:

As a ‘single’ user I tend to focus on the hardware I know, and sometimes forget that things are always more complex than they seem. Besides changing all the time. That’s part of the pain (and joy) of computing…