System.img or System.sfs

[Thisara Kasun]

Hi,
I'd like to know whether there are any benifits or drawbacks in the squashfs approach,performance gain or cost of boot time? Or is it just for saving space?

[Midi Jari]

SFS or squashfs is just compressed system.img file, as the img file keeps the blank space (as if it is a real volume) while squashfs compress it and removes the blank space and that saves the in the iso size after compiling. and running an OS from sfs is always (well... most of the time) transferred to ram, so myeah! like running android from ram, and the system is literally write protected. Performance wise (if you mean booting up) I cannot give you an answer as it's very fast on my system either way (ssd + i7 and plenty of fast ram).

[Ildar Mulyukov]

воскресенье, 24 июля 2016 г., 18:44:50 UTC+6 пользователь Thisara Kasun написал:

> Hi,
> I'd like to know whether there are any benifits or drawbacks in the squashfs approach,performance gain or cost of boot time? Or is it just for saving space?

1. AFAIK squashfs adds a small delay during the boot
2. requires extra RAM for decompressed blocks (files). I don't know how optimized the kernel module is for small RAM sizes. Big RAM should benefit from this fs (due to faster IO)
3. system.img is modifiable if you need to

IMHO don't think the squashfs approach is ideal here. For storing system.img the sparse allocation can be used, for ISO the RockRidge compression can be used.

Best regards, Ildar.