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Create large 1G Ramdisk on Red Hat Enterprise 4 Linux

Might as well put this up because I had a bit of a time finding info on this. The question is, how do you make a large ramdisk on linux (specifically for me, Red Hat Enterprise 4). Took a combination of other people's posts to put it together.

The basics are:
1. Edit /etc/grub.conf to add ramdisk_size = xxx (in kb) at the end of the 'kernal' line. I wanted to get a 1G ramdisk, so: ramdisk_size = 1000000

2. Reboot.

3. Double check things are ok: dmesg | grep RAMDISK

4. Then format the disk. I want the whole 1G in one disk. And here's the little tidbit. Apparantly, the default behavior for mke2fs is to create block sizes of 1024 for ramdisk sizes <= 512M. For larger sizes, it creates block sizes of 4096. If you use the default, you'll get the error something like this:
"wrong fs type, bad option, bad superblock on /dev/sda1, or too many mounted file systems"
when you try to mount your ramdisk.

So you need to do this:
mke2fs -b 1024 -m 0 /dev/ram0
(-m is optional; use if you don't want space reserved for root user)

5. Now you can mount the ramdisk: mount /dev/ram0 /var/mountpoint

6. Check to see if all is well with: df

And there you have it. A big ramdisk.

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