(SOLVED) How many swap partitions

If one computer have two or more operating systems "installed", is it enough to have a common swap partition for all os.es? This question came up when I installed the thirth os. to an ext. USB drive and the installation process suggested to check whether I will make a swap partition to the USB Drive.

I did not make it due to I know that there already is one 2.1 Gb swap partition on my HDD where I have a Ubuntu 14.04 and Zorin 8 Ultimate installed alongside as dual boot. However I am not sure whether that swap partition can be used when running an os. which is installed on a ext. memory device like USB drive.

I believe that the os. on a USB (or some ext. HDD or SSD) uses only CPU and RAM and can not use the swap partition on the internal HDD. So in that case there should be an own swap partition on the USB drive also, to improve the memory usage and performance of the os. However I did not find anywhere a clear answer for that.

Hi,

1 swap should be enough, for more detailed info about swap:

https://help.ubuntu.com/community/SwapF ... _I_need.3F

Thanks, also this text taken from the linked document convinced me that 1 swap partition is enough and almost recommnded to be located in an other disk device.

"Optimizing Swap performance Because swap space uses a disk device, this can cause performance issues in any system that uses swap space significantly because the system itself may also be using the same disk device at the same time that it is required for swap operations. One way to reduce this problem is to have swap space on a different physical drive so that the competition for that resource is either reduced or eliminated."