Ramdisk for entire OS?

[jon_p]

There's a great article on using Ramdisk by Van Emery (wish i could post a link, just google it) that explains in clear detail how to move a folder into RAM for both security and speed.

I would like to put my entire Red Hat server into RAM to both speed up my system and to limit writes to my drives.
As solid state drives are becoming more popular, the question of longevity is becoming a bigger issue as these drives have a limited number of write cycles.
If my data and swap are both in RAM, this limits the usage of the drives themselves.

How can I boot my system, make a ramdisk with everything on it, and then make sure that RHEL is running directly from memory and not my drives?

Thanks in advance.

[jon_p]

I was reading (http ://en.wikipedia.org/wiki/Tin_Hat_Linux) how Tin Hat Linux uses SquashFS to expand the tmpfs when booting.

Any ideas how to change the RHEL boot to do this?

[reed9]

I would look at Puppy Linux or Slax and see how they do it.

howpuppyworks.html
polishlinux.org SLAX 6.0: How does it work?
Linux initial RAM disk (initrd) overview

[jon_p]

I would look at Puppy Linux or Slax and see how they do it.

Thanks reed9 for the links, they were helpful.

However I still have a few questions. Puppy for example puts all working files into ramdisk, the persistent storage into a separate ext3 file, and the rest (apps, scripts, whatever) into a squashfs file. My goal is to put EVERYTHING onto the ramdisk, or just a tmpfs so that i never write to the system disk. Any thoughts on this?

I think i can accomplish this with initrd but i'm kinda new to linux and i feel like i'm in way over my head here. I would appreciate any feedback. Thanks!

[reed9]

You're going to have to have files stored on a physical disk somewhere. Is your goal a live CD or USB? You're not interested in any files or changes being persistent across boots?

[reed9]

This might be of interest to you.
HOWTO: Load linux into ram (usefull for security, CF-cards or very slow HDD's) - Ubuntu Forums

[jon_p]

This might be of interest to you.

Thank you, this is a tremendous help for Ubuntu! Exactly what I want to do.

However, there are a few packages missing in Red Hat (squashfs, aufs). I'm in the process of tracking down whoever has the license to download the missing RPM's. In the meantime, do you see any problem with implementing this in Red Hat?

[jon_p]

You're going to have to have files stored on a physical disk somewhere. Is your goal a live CD or USB? You're not interested in any files or changes being persistent across boots?

Yes, I basically want to operate the same way a live CD works, except instead of loading from the CD i'll have a hard drive that puts my OS into RAM.

It is not necessary for changes to be persistent across boots... but it would be nice to have the option to save back to the hard drive.