Creating bigger RAM DISK

[sathiya]

Am trying to create a RAMDISK of 1 GB in a 2 GB RAM.

But it is only possible to create 512 MB RAMDISK.

While searching i found that it is possible to create 25% of RAM as RAMDISK.
We want to increase a kernel parameter to create a bigger RAMDISK


Will you please help me what to do ?

Which kernel configuration i need to change for this ??

and how could i change this ?

[wowbag1]

have a look at this link:
Whatever....: RAM disk in linux

To quote a bit of it
"# grub.conf generated by anaconda
#
# Note that you do not have to rerun grub after making changes to this file
# NOTICE: You do not have a /boot partition. This means that
# all kernel and initrd paths are relative to /, eg.
# root (hd0,4)
# kernel /boot/vmlinuz-version ro root=/dev/hda5
# initrd /boot/initrd-version.img
#boot=/dev/hda
default=0
timeout=5
splashimage=(hd0,4)/boot/grub/splash.xpm.gz
hiddenmenu
title Fedora Core (2.6.11-1.1369_FC4)
root (hd0,4)
kernel /boot/vmlinuz-2.6.11-1.1369_FC4 ro root=LABEL=/1 ramdisk_size=512000 quiet
initrd /boot/initrd-2.6.11-1.1369_FC4.img
title Windoze XP
rootnoverify (hd0,1)
chainloader +1


The above configuration file would create ramdisks of size 512MB. There is an upper limit to the max size of RAMDISK that can be created and it is also controlled by the amount of available RAM. So if you have 512MB of RAM, you would not be able to create RAMDISKS of more than 512MB. But depending on the kernel configuration, if you have a 4GB RAM system, you may not be able to create RAMDISK of more than 1GB maybe. You will have to check this limit either with the kernel documents or by trying out different sizes at boot prompt.

Try this link as well:Linux initial RAM disk (initrd) overview
Hope this helps

[wowbag1]

I have also found this - which maybe more like what you are looking for:

+The RAM disk supports up to 16 RAM disks by default, and can be reconfigured
+to support an unlimited number of RAM disks (at your own risk). Just change
+the configuration symbol BLK_DEV_RAM_COUNT in the Block drivers config menu
+and (re)build the kernel.
+
+To use RAM disk support with your system, run './MAKEDEV ram' from the /dev
+directory. RAM disks are all major number 1, and start with minor number 0
+for /dev/ram0, etc. If used, modern kernels use /dev/ram0 for an initrd.

The new RAM disk also has the ability to load compressed RAM disk images,
allowing one to squeeze more programs onto an average installation or

This is in Ramdisk.txt of the kernel documentation, link is:
Linux Headquarters - Patches for file /Documentation/ramdisk.txt

[sathiya]

A great thanks for your reply.........


The procedures what ever you said have been followed already, and i said in my first post that am not able to create more than 512 MB of RAMDISK, instead of saying like this, i can say....

Am not able to create a RAMDISK of more than 25 % of RAM, this would be much clear......


So here my problem's solution would be how to change this....

The pages whatever you referred gives me the same, using that am unable to create more than 25% of RAM as RAMDISK.....


so how to do that .........???????? ( creating bigger RAMDISK ) !!!!!