(SOLVED) How many logical partitions can you have?

Google · 2010-06-10 03:07:57

Hello, I guess this is my "Setting up my second Arch install!" thread. In my first thread I setup Arch on my desktop, and now I want to make my laptop, almost, Arch exclusive. I want one free primary partition for the future, but..

How many logical partitions can you have in one extended partition? I want to know if I can partition/divide up my laptop Arch installation inside of one extended partition.

Something like this is what I would like to go for:

sda
sda1 primary - ext4 /storage
sda2 primary extended
sda3 logical /boot ext2
sda4 logical / ext4
sda5 logical swap
sda6 logical /home ext4
sda7 logical /var reiserfs
sda8 logical /tmp reiserfs

I don't mind using 3 primary partitions if I must, but at the end I need one primary available (for ChromeOS, when it's officially released in November).

Is there any negative side effects to using logical partitions as opposed to primary?

Thanks--

Last edited by Google (2010-06-10 04:57:06)

fsckd · 2010-06-10 03:51:50

I was going to suggest you Google for an answer but seeing you are Google ... my money is on 15 (sort of wrong see edit below) judging by major/minor numbers.

Edit: Oops. I should clarify. There are 16 minor numbers allocated per drive on my system. One goes to the drive itself. So 15 remain for logical and primary partitions together. So if you have all logical the containing primary would probably not get any and you could have 15 logical at most. If you have one primary that would leave 14 left over, etc. At most you can use 3 primaries and that would leave 12. Remember, this is just educated guesses from me. By my hardware, I should have more (I think 63? I'll have to check using magical means). I wonder what would happen if I have more in hardware than what the OS would allow. Hmm ... Oh yeah, other OSes might see things a little different too, especially if you use something exotic such as Hogfarb's Resplendent Operating System.

Last edited by fsckd (2010-06-10 04:04:02)

Google · 2010-06-10 04:01:32

I 'Googled' it but I didn't seem to get the answer I was looking for. I found a lot of, "A hard drive should contain only one extended partition" and a bunch of stuff that isn't too related. I may have been wording it strangely, but thanks for the number. Very helpful sir

If it isn't too much to ask, is there any reason why people choose primary partitions over logical?

sand_man · 2010-06-10 04:14:38

I read that the maximum number of partitions (limited by the kernel) is 63. 4 primary partitions and 59 logical.
I can't find a solid source on this though. I just saw the answer here http://www.linuxforums.org/forum/instal … linux.html

Inxsible · 2010-06-10 04:23:06

Google wrote:

.............
I don't mind using 3 primary partitions if I must, but at the end I need one primary available (for ChromeOS, when it's officially released in November).
Is there any negative side effects to using logical partitions as opposed to primary?
Thanks--

The question here would be : Does ChromeOS require a primary partition for installation?

The all-knowing Wikipedia says, that Chrome OS is based on Linux and is Unix-like operating system. So I would say that no, you don't need to reserve a primary partition for an OS which might be released 6 months later. Just do your thing now, and you can always create some space and a logical partition then and run ChromeOS.

Last edited by Inxsible (2010-06-10 04:26:39)

fsckd · 2010-06-10 04:30:32

Google wrote:

I 'Googled' it but I didn't seem to get the answer I was looking for. I found a lot of, "A hard drive should contain only one extended partition" and a bunch of stuff that isn't too related. I may have been wording it strangely, but thanks for the number. Very helpful sir
If it isn't too much to ask, is there any reason why people choose primary partitions over logical?

Ahh, might I point out I was in the middle of an edit? Let me see if I can answer your logical vs primary question. Most of this should be prefaced with "IIRC". The MBR is only aware of the primary partitions. These are limited to four because, that's what it allows. To get logical (extended) partitions, a primary partition is divided further. Not all OSes follow the same scheme for logical partitions but most do. The advantage of using them, of course, is you get more partitions to work with. ^^

Regarding the scheme most OSes, including Linux use, the structures describing the logical partitions is called the extended boot record which resides in the logical partitions themselves. I don't know much about this, but according to Wikipedia, there is a theoretical limit of unlimited, or "as much as there is space for". This means, any hard limits like 15 or 63 is set by the OS. *shrugs*

Google · 2010-06-10 04:56:54

Thanks a lot, I have found all of your replies more than great and I think this is solved

I am on to another topic concerning partition layouts and the connection with performance. I was going to ask here but another user created a topic for it: http://bbs.archlinux.org/viewtopic.php? … 26#p772626

Thanks a lot for your help!

Arch Linux

#1 2010-06-10 03:07:57

(SOLVED) How many logical partitions can you have?

#2 2010-06-10 03:51:50

Re: (SOLVED) How many logical partitions can you have?

#3 2010-06-10 04:01:32

Re: (SOLVED) How many logical partitions can you have?

#4 2010-06-10 04:14:38

Re: (SOLVED) How many logical partitions can you have?

#5 2010-06-10 04:23:06

Re: (SOLVED) How many logical partitions can you have?

#6 2010-06-10 04:30:32

Re: (SOLVED) How many logical partitions can you have?

#7 2010-06-10 04:56:54

Re: (SOLVED) How many logical partitions can you have?

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