hillyu Posted April 17, 2009 Share Posted April 17, 2009 Hi I am extremely happy to find out there is already a built in method called shadow which is identical to the unionfs under linux system, at first I wanted to make a ro root and use uninonfs to attach a writable fs to it and make the system apears to be writable, but thanks to the shadow, all those processes are simplified dramatically.(besides I am not sure the unionfs is supported by osx) why i want this is basiclly because I want to make my eeepc901(16g mlc ssd) more speedly, because the old 16g mlc has really bad performanc at 4k writing which lead to a laggy performanc. what I plan to do is to mount my root read-only first and then attach a ramdisk as a shadow to it, this will make all writing to the root extreamly fast due to the actrual writing is taken place on ram. later I can easily mount the /users to a built in 4g slc in normally readable mode to store my personal data, if you want to protect the data, you can left the whole root read-only. To achieve this I only need to twik the boot script a little bit, and I do not need a whole system img to load into my ram at all, I am not building a "live cd" but a "shadow system". But there is a question left, i don't know if there is a default boot script by modify which I do not need to boot into single user first and using the command to initial my "netboot" script. or if there is a method to load this script automatically. Link to comment Share on other sites More sharing options...
hillyu Posted April 18, 2009 Author Share Posted April 18, 2009 I made a mistake, shadow can only apply to the disk images, not the real disk. so I have to resort to the union fs method, but I think I can not simply create a overlay over the root, under llinux, I can change the initrd to control the root's mounting process, but I don't know where to find such a thing, After loading the kernel, what exactly happen following.I think this is a key problem. Link to comment Share on other sites More sharing options...
spartango Posted January 21, 2010 Share Posted January 21, 2010 You might also try making a shutdown script to save the shadow file to disk(make all the writes at once) and then restore that to RAM on bootup. Link to comment Share on other sites More sharing options...
Recommended Posts