antiX-FAQ
Persistence Options

## What is Persistence?

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Persistence is a hybrid between a LiveCD/USB and a full install. One of the beauties of a LiveCD is that it allows you to boot Linux without touching any hard drives so you can have a "test-drive" without fear of altering your current system. Another feature of a LiveCD is that once it is burned, it is close to impossible for it to get infected with a virus or a Trojan horse. Every time you boot it, you start off with a system that is clean and pristine.

Persistence gives you a way of remembering things between boots. In order to do so, it needs access to a read-write device, typically either a hard drive or a USB stick. If you are only using one machine that is yours then you can put the persistence file(s)s on one of your hard drives.

## Four Kinds of Persistence

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The antiX distribution offers up to four different forms of persistence on our Live Media (LiveCD/DVD/USB, etc). Remastering is only available on writable media such as a LiveUSB or a LiveHD (frugal install) not a CD or DVD. All four forms can be used together if desired. They each have different strengths and weakness which are important to understand in order choose the right method or methods for your purposes.

### Home Persistence

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Home persistence is the simplest and safest. The `homefs` persistence file is mounted at `/home`. Any changes made to files under `/home` are (nearly) instantly stored on `homefs` filesystem. It is good if you want to save settings (such as bookmarks or changes to your desktop) but it doesn’t save changes made to the system (such as installing packages). Generally, if you need the root password to do it then it is not saved. Home persistence is also ideal if you want to download and save a lot of data. It is the safest precisely because you can’t save any system changes with it. Even if your system gets compromised, it will be very difficult for the bad guys to make any permanent changes to your system.

### Root Persistence

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Root persistence allows you to save changes to the system in addition to saving personal settings. It has two significant limitations. These limitations are due to the fact that as the system is running the changes are stored in RAM and will be lost unless they are specifically copied back to the `rootfs` file. If your computer crashes before the changes are copied back then your changes will be lost. The other limitation is that the amount of new information you can store is limited by how much free RAM you have.

Dynamic root persistence saves file system changes in RAM (just like a normal LiveCD/USB). The persist-save program must be run to copy these changes to the rootfs file so they can be remembered across reboots. Use persist-config to have the program run automatically on shutdown/reboot.

### Static Root Persistence

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Static root persistence is another way to use persistence. Static root persistence saves file system changes directly in the rootfs file. It does not use any RAM so the only size limit is the size of the rootfs file. This makes it good for doing an "apt-get upgrade" or for installing a bunch of packages. It is usually best to follow up with a Live remaster to consolidate the file system changes into the compressed squashfs file. On many systems, static root persistence can be annoyingly slow. You are free to switch between static and dynamic root persistence each time you boot.

### Frugal Installation

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If you have access to a hard drive, you may wish to run antiX from it live with or without persistence. Using persistence is recommended. The main advantage of running frugally is that it is very fast and saves space since it uses the compressed squashfs (linuxfs) which is typically 4 times smaller than installed to hard drive. antiX has made setting up frugal very easy. Just press F5 at the boot menu and choose the frugal option. See How do I Create Persistence Files? below for further details.

### Remastering

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We include remastering as a form of persistence for purposes of comparison. The Remastering page contains implementation details. If root persistence is like using a piton while climbing up a cliff, remastering is more like setting up a camp or bivouac site.

## How does it Work?

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The information for both root and home persistence is stored in two files called `rootfs` and `homefs`. Unlike previous versions of antiX, there is no longer an option to use a entire partition for root or home persistence. The default location for these files is right next to the squashfs file, on the same device and in the same directory. We suggest that you use this default location whenever possible, but sometimes it is not possible (such as when booting from a LiveCD or LiveDVD). For these cases you can specify which device the persistence files are on. You can also specify a different directory.

## How do I Create Persistence Files?

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### Automatically

The `homefs` and `rootfs` persistence files can be created when booting at the live desktop menu. Press F5, choose the persist option and on boot you will be prompted to set it up. You will be first asked where you want to save the persistent file(s). You just need to decide how large you want to make the file(s). The ext4 file system will be used. Once the `homefs` and `rootfs` files have been created, you will be prompted to make changes to the root and user passwords. This is for security. The final step will ask you how you want to set the save mode for root persistence. Options include: Automatic, Semi_Automatic and Manual Save. On reboot/halt any changes will be saved.

Note: If you have your persistence file(s) on a separate device to the one you boot from, you must specify your persistence device. You can use the following: * pdev=sda1 ie persist device * plab=antiX-Persist ie label of the device where persistence files are kept * puuid=xxxxxxx ie the uuid of the device.

### Manually by Using the live-usb-maker app

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You can run antiX live from a usb stick. To install to usb stick you can use our tool live-usb-maker.

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## Video

antiX 17 - Make a live-USB with persistence! https://www.youtube.com/watch?v=qq0mRZh2hiY&t=2s

Remaster your antiX live-USB https://www.youtube.com/watch?v=LpI_a4xPKdM&t=2s

by runwiththedolphin