I want to install centOS 7 along side windows 8.1 for this I'm planning to do partition in a following way.

/boot - 500MB - Standard Partition
/swap - Half of my RAM size
/root - 20GB - Standard Partition
/home - Rest of my space - Standard Partition

The problem is: if I create /swap first, then I couldn't create Standard Partition anymore. Likewise if I create Standard first, I couldn't create /swap.

The error message is: Unable to allocate requested partition scheme.

After research, I understand that my MBR disk can not have more than 4 primary partition. Here is the current status of my disk

My Partition

As per as my understanding, Windows already took 3 primary partition

System (C)
System Reversed (E)
Extended Partition (container of Data and AOMEI Recovery Partition)

and CentOS require 2 more Primary Partition: one for /boot and one for the rest (correct me this part if I'm wrong)

Now I have no idea what I should do next to fix this problem. Should I change the setup of CentOS partition or do something to reduce the number of Primary Partitions on Windows and how to do this without losing data.

  • 1
    centos does not require any primary partitions. linux has no difficulty booting from extended partitions. – cas Jan 5 '18 at 6:32
  • if you want to avoid repartitioning that disk, your best bet is to just have a single partition with /, /boot, /home, and everything else on it (i.e. that 115GB unallocated partition), and use a swap file instead of a swap partition (or don't bother with swap at all). Alternatively, install Virtual Box and run Centos in a VM. Yet another alternative is to use LVM (centos installer should offer this automatically) and it will make LVM volumes as needed from that 115GB unallocated partition. – cas Jan 5 '18 at 6:36
  • When I try to set LVM volumes for all my disk, the installer said that "/boot can not be LVM". I don't remember the full sentence exactly. Are there any problems if I remove swap partition? Every tutorial I read on the Internet told me that swap is neccessary :( – Huy Jan 5 '18 at 8:24
  • does the centos installer give you the option of not having a /boot partition? e.g. "install on one big filesystem" or words to that effect? RE: swap - how much RAM do you have, and what do you expect to be using the system for? btw, you can always use a swapfile - they're a bit slower than using a swap partition, but it works. – cas Jan 5 '18 at 9:24
  • swap is useful but not absolutely necessary. running out of RAM is no different to running out of RAM+SWAP, it just happens a little sooner. – cas Jan 5 '18 at 9:25

Here is the way I solved this problem:

Move 115 GB unallocated (the one with black bar) into the Extended Partition. Then it would become freespace (with green bar). Now you can install CentOS on this free partition. I used EaseUS to move the partition.

Before partition format (not working):

System Reversed (E)
Unallocated Space
System (C)
Extended Partition (container of Data, AOMEI Recovery Partition)

Working partition format:

System Reversed (E)
System (C)
Extended Partition (container of Data, AOMEI Recovery Partition, Free space)


To circumvent the 4 primary partitions limit, you can create an extended partition in lieu of a primary partition, and then split it in four logical partitions (/, /boot, /swap, and /home).

Also, in the CentOS installer, choose the option to re-format these partitions (except the swap of course). It solved the problem for me when I had the same error message.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.