Extended Partition

In preparation for 11.0 it is time to remove Windows XP completely. It’s
very rarely used nowadays and when it is VirtualBox fits the bill
perfectly. I have the following partitions :

Device Boot Start End Blocks Id System
/dev/sda1 1 1307 10498446 7 HPFS/NTFS
/dev/sda2 * 1308 12161 87184755 f W95 Ext’d (LBA)
/dev/sda5 1439 4049 20972857+ 83 Linux
/dev/sda6 4050 4311 2104483+ 82 Linux swap / Solaris
/dev/sda7 5623 9279 29366820 83 Linux
/dev/sda8 9280 12161 23157634+ 83 Linux

In using the whole disk for Linux I assume I will no longer need/have the
extended partition (/dev/sda2). Will this give me any benefits?


Linux user 359911
openSuSE 11RC1
Dell Inspiron 9300

If you need 4 or less partitions, you can do without extended partitions and make them all primary. You won’t save much space, an EP is just a container for logical partitions. However it will make it somewhat easier to resize partitions, as it’s hard to merge a logical partition with a primary partition. Other than that, it just looks neater without EPs.

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The extended partition will only be needed if you want more than four
partitions regardless of the OS. If you only have ‘/’ and swap you
definitely won’t need it and it will gain you nothing, but if you want
‘/’, swap, /home, /var, and something else then you will need an
extended partition defined to create two logical partitions to meet your
needs.

Good luck.

AussieBob wrote:
| In preparation for 11.0 it is time to remove Windows XP completely. It’s
| very rarely used nowadays and when it is VirtualBox fits the bill
| perfectly. I have the following partitions :
|
| Device Boot Start End Blocks Id System
| /dev/sda1 1 1307 10498446 7 HPFS/NTFS
| /dev/sda2 * 1308 12161 87184755 f W95 Ext’d (LBA)
| /dev/sda5 1439 4049 20972857+ 83 Linux
| /dev/sda6 4050 4311 2104483+ 82 Linux swap /
Solaris
| /dev/sda7 5623 9279 29366820 83 Linux
| /dev/sda8 9280 12161 23157634+ 83 Linux
|
| In using the whole disk for Linux I assume I will no longer need/have the
| extended partition (/dev/sda2). Will this give me any benefits?
|
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ab@novell.com wrote:

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>
> The extended partition will only be needed if you want more than four
> partitions regardless of the OS. If you only have ‘/’ and swap you
> definitely won’t need it and it will gain you nothing, but if you want
> ‘/’, swap, /home, /var, and something else then you will need an
> extended partition defined to create two logical partitions to meet your
> needs.
>
> Good luck.
>
>
>
>
>
> AussieBob wrote:
> | In preparation for 11.0 it is time to remove Windows XP completely. It’s
> | very rarely used nowadays and when it is VirtualBox fits the bill
> | perfectly. I have the following partitions :
> |
> | Device Boot Start End Blocks Id System
> | /dev/sda1 1 1307 10498446 7 HPFS/NTFS
> | /dev/sda2 * 1308 12161 87184755 f W95 Ext’d (LBA)
> | /dev/sda5 1439 4049 20972857+ 83 Linux
> | /dev/sda6 4050 4311 2104483+ 82 Linux swap /
> Solaris
> | /dev/sda7 5623 9279 29366820 83 Linux
> | /dev/sda8 9280 12161 23157634+ 83 Linux
> |
> | In using the whole disk for Linux I assume I will no longer need/have
> | the extended partition (/dev/sda2). Will this give me any benefits?
> |
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Thanks Guys, that clears it up for me, I had thought the 4 Partition limit
was only for Microsoft O/S. Would I still need a Primary (probably /
eg /dev/sda1) and the remainder extended if I needed more than 4
Partitions?


Linux user 359911
openSuSE 11RC1
Dell Inspiron 9300

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Yes.

Good luck.

AussieBob wrote:
| ab@novell.com wrote:
|
| The extended partition will only be needed if you want more than four
| partitions regardless of the OS. If you only have ‘/’ and swap you
| definitely won’t need it and it will gain you nothing, but if you want
| ‘/’, swap, /home, /var, and something else then you will need an
| extended partition defined to create two logical partitions to meet your
| needs.
|
| Good luck.
|
|
|
|
|
| AussieBob wrote:
| | In preparation for 11.0 it is time to remove Windows XP completely. It’s
| | very rarely used nowadays and when it is VirtualBox fits the bill
| | perfectly. I have the following partitions :
| |
| | Device Boot Start End Blocks Id System
| | /dev/sda1 1 1307 10498446 7 HPFS/NTFS
| | /dev/sda2 * 1308 12161 87184755 f W95 Ext’d (LBA)
| | /dev/sda5 1439 4049 20972857+ 83 Linux
| | /dev/sda6 4050 4311 2104483+ 82 Linux swap /
| Solaris
| | /dev/sda7 5623 9279 29366820 83 Linux
| | /dev/sda8 9280 12161 23157634+ 83 Linux
| |
| | In using the whole disk for Linux I assume I will no longer need/have
| | the extended partition (/dev/sda2). Will this give me any benefits?
| |
| Thanks Guys, that clears it up for me, I had thought the 4 Partition limit
| was only for Microsoft O/S. Would I still need a Primary (probably /
| eg /dev/sda1) and the remainder extended if I needed more than 4
| Partitions?

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The 4 primary partition limit is due to the layout of the MBR in the PC architecture.

Thanks Guys, that clears it up for me, I had thought the 4 Partition limit
was only for Microsoft O/S. Would I still need a Primary (probably /
eg /dev/sda1) and the remainder extended if I needed more than 4
Partitions?

The rule is simple. There are 4 slots for partition information in MBR. There can be only 1 extended and it is special type of primary partition. So if you have 1 extended you can have maximum 3 primaries. The old DOS rule is that there has to be at least one primary (which is not extended), but I’m not sure that grub needs that. That is considering BIOS and starting grub.

Linux currently supports up to 15 partitions. The reason is that libata supports up to 16 devices, where 0 is controller, so 15 device numbers can be used for partitions. It used to be much more in Linux, but this is a current state.

You can use /dev/sda1 for swap, /dev/sda2 for root / and /dev/sda3 for /home. If you want to install another Linux than you can resize /home and add extended partition where you can create up to 12 logical partitions.

rajko m wrote:

>
>> Thanks Guys, that clears it up for me, I had thought the 4 Partition
>> limit
>> was only for Microsoft O/S. Would I still need a Primary (probably /
>> eg /dev/sda1) and the remainder extended if I needed more than 4
>> Partitions?
>> The rule is simple. There are 4 slots for partition information in MBR.
> There can be only 1 extended and it is special type of primary
> partition. So if you have 1 extended you can have maximum 3 primaries.
> The old DOS rule is that there has to be at least one primary (which is
> not extended), but I’m not sure that grub needs that. That is
> considering BIOS and starting grub.
>
> Linux currently supports up to 15 partitions. The reason is that libata
> supports up to 16 devices, where 0 is controller, so 15 device numbers
> can be used for partitions. It used to be much more in Linux, but this
> is a current state.
>
> You can use /dev/sda1 for swap, /dev/sda2 for root / and /dev/sda3 for
> /home. If you want to install another Linux than you can resize /home
> and add extended partition where you can create up to 12 logical
> partitions.
>
>

Again not to sound too stupid, if I had 4 Primary Partitions (/ [/dev/sda1]
swap [/dev/sda2] /home [/dev/sda3] /XXXX [/dev/sda4]) if I needed more in
the future I could remove /XXXX and make it an extended Partition and have
multiple mount points within it.


Linux user 359911
openSuSE 11RC1
Dell Inspiron 9300

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Yes. You would make /dev/sda4 an extended partition (which isn’t
directly usable) and then create /dev/sda5 to /dev/sdaN for whatever
else you needed as Logical Partitions. Four primaries as you have is
valid but to get more you must change one to extended and make it (and
others) logical.

Good luck.

AussieBob wrote:
| rajko m wrote:
|
|>> Thanks Guys, that clears it up for me, I had thought the 4 Partition
|>> limit
|>> was only for Microsoft O/S. Would I still need a Primary (probably /
|>> eg /dev/sda1) and the remainder extended if I needed more than 4
|>> Partitions?
|>> The rule is simple. There are 4 slots for partition information in MBR.
|> There can be only 1 extended and it is special type of primary
|> partition. So if you have 1 extended you can have maximum 3 primaries.
|> The old DOS rule is that there has to be at least one primary (which is
|> not extended), but I’m not sure that grub needs that. That is
|> considering BIOS and starting grub.
|>
|> Linux currently supports up to 15 partitions. The reason is that libata
|> supports up to 16 devices, where 0 is controller, so 15 device numbers
|> can be used for partitions. It used to be much more in Linux, but this
|> is a current state.
|>
|> You can use /dev/sda1 for swap, /dev/sda2 for root / and /dev/sda3 for
|> /home. If you want to install another Linux than you can resize /home
|> and add extended partition where you can create up to 12 logical
|> partitions.
|>
|>
|
| Again not to sound too stupid, if I had 4 Primary Partitions (/
[/dev/sda1]
| swap [/dev/sda2] /home [/dev/sda3] /XXXX [/dev/sda4]) if I needed more in
| the future I could remove /XXXX and make it an extended Partition and have
| multiple mount points within it.
|
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