2

What I want - A flashdrive that can boot multiple versions of Ubuntu, (from iso files), each with it's own persistent partition.

What I don't want - A flashdrive with a persistent file limited to 4GB, or a multibooter with only one persistent partition.

Home-rw files or partitions don't count, Full installs don't count.

I want to be able to update by dragging and dropping new Ubuntu iso's onto the drive.

The keyword here is MultiPersistence, I could not find the answer in Google or in previous posts.

UPDATE

Sundar Ima, gives a hint at a solution in MultiBootUSB V8, adding "persistent-path=/(folderx)/" after "persistent" in the grub2 menuentry. This allows the use of multiple casper-rw files on the same disk.

For example:

menuentry "ubuntu1.iso" {
set root=(hd0,1)
loopback loop /isos/ubuntu1.iso
linux (loop)/casper/vmlinuz.efi boot=casper persistent persistent-path=/casper1/ iso-scan/filename=/isos/ubuntu1.iso noeject noprompt --
initrd (loop)/casper/initrd.lz
}

menuentry "ubuntu2.iso" {
set root=(hd0,1)
loopback loop /isos/ubuntu2.iso
linux (loop)/casper/vmlinuz.efi boot=casper persistent persistent-path=/casper2/ iso-scan/filename=/isos/ubuntu2.iso noeject noprompt --
initrd (loop)/casper/initrd.lz
}

The first menuentry boots an iso named "ubuntu1.iso" located in the folder named "isos" using the casper-rw file located in the folder named "casper1".

The second menuentry boots an iso named "ubuntu2.iso" located in the folder named "isos" using the casper-rw file located in the folder named "casper2".

The problem is that the size of the casper-rw files is still limited to 4GB. ( I will try AlexatUnuntu's solution just in case things have changed in the past few years).

Having a limited understanding of grub2, I think the solution to multiple persistent partitions is to use "persistent-path=" to point to the desired casper-rw partition for each iso's menuentry, but how?

2

The maximum work space for persistence is 8 GiB (not 4 GiB). The casper-rw file is maximum 4 GiB and the home-rw file is also maximum 4 GB. But there are restrictions, max 4 GiB for the system (installed programs) and max 4 GiB for tweaks and personal files.

It is possible to have an extra data partition for huge files like video clips, so maybe these 8 GiB will be enough for many users, who want multibooting with persistence for more than one of the systems.

This works with a FAT32 file system and with adding

persistent-path=/(folderx)/

after "persistent" in the grub2 menuentry for each iso file to get separate storage for persistence in a multiboot pendrive.

  • Another good answer Sudodus, not perfect but very good. I am starting to understand that persistent path can only refer to folders and not partitions. – C.S.Cameron Dec 1 '16 at 6:52
2

NTFS file system i believe lets you have a lot more than 4GB which i think is the limit for FAT32 file systems.

You should be able to drag and drop your iso image into your drive after that. remember NTFS file system when formating your USB.

Hopes it helps a bit just trying to get Ubuntu points to be honest.

  • Thanks AlexatUnuntu but I want multiple persistent partitions, one for each iso, I have never been able to get casper-rw to work on a NTFS partition. – C.S.Cameron Nov 17 '16 at 6:32
  • I gave it another try AlexatUnuntu, I was able to boot iso files located on a NTFS partition, (which is good to know), but persistence files located on the NTFS partition still do not work. Consider yourself lucky that I could not give half marks. – C.S.Cameron Nov 18 '16 at 5:28
  • Have you considered accepting an answer or starting a bounty for this question? - Please note that this is not an acceptable answer, It does not offer a solution to multiple persistent partitions, or multiple persistence over 4GB, which is what the question is about. – C.S.Cameron Nov 22 '16 at 3:30
  • @ C.S.Cameron, congratulations to a great solution by combining your own ideas with ideas and methods from several different people! – sudodus Dec 1 '16 at 5:39
1

Update 08/2017:

Syslinux started adding support for NTFS with version 4.06 but did not offer full support until version 6.03.

UNetbootin - 655 uses Syslinux 4.03 and is limited to 4GB persistence files per FAT32.

MultiBootUSB - 8.8 uses Syslinux 4.07 and will install on NTFS, persistence files are not limited to 4GB. The Linux version will install the bootloader on ext file systems.

Rufus 2.16 uses Syslinux 6.03 and will install on NTFS, persistence files are not provided but can be added manually and are not limited to 4GB.

YUMI - 2.0.4.9, (MultiBoot USB), uses Syslinux 6.03 and will install on NTFS, persistence files are not limited to 4GB. Like MBUSB 8.8 it can have large persistence files for each distro installed.

  • @Sudodus: I just installed a syslinux boot to an ext4 drive using MultiBootUSB (Linux version). There are possibilities in this I think. – C.S.Cameron Aug 15 '17 at 22:24
  • Do you mean that syslinux supports not only NTFS but also ext4 file systems now? Does it work both in BIOS mode and UEFI mode? Or do we still need grub to boot in UEFI mode? – sudodus Aug 16 '17 at 5:59
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    MultibootUSB will install to ext4 but persistence does not work there. Switched laptop to UEFI mode, Yumi NTFS boots, casper-rw files work, (YUMI has no grub.cfg file). MultiBootUSB ext4 initially uses syslinux menu then uses grub.cfg to boot OS, it will boot in UEFI mode but only 32bit, so far. – C.S.Cameron Sep 3 '17 at 22:56
  • The syslinux installer for ext is extlinux, manpages.ubuntu.com/manpages/yakkety/man1/extlinux.1.html – C.S.Cameron Sep 5 '17 at 15:43
0

Easy2Boot allows you to have multiple casper-rw files for multiple ISOs. It boots directly from ISO files and uses NTFS. You can also create multiple, fully installed linux OS's using .imgPTN files.

  • Does it work with casper-rw files over 4GB? YUMI does something with grub4dos that allows large persistence files, sorta like a virtual partition. I have not got this to work with most other USB makers. Only casper-rw files made using YUMI seem to work, ones made using dd or the pendrivelinux tool don't work for me when copied to YUMI. – C.S.Cameron Dec 28 '17 at 12:59

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