Ramdisk size, howto increase limit (Kernel parameters)

Hi everyone,

I wanted to create ramdisks but its size is limited to 16megs only. I wanted to increase it and found that it can be increased via kernel parameters while booting.

Can we do the same while the machine is running?
May be through some fine tunable parameter in /proc/sys/kernel ?

Thanks in advance,

Hey guys,

If it is impossible, please tell me so, So that I won't keep waiting for the answer.


I Hope some one will answer,


Bye

As far as I know, the size of ramdisks cannot be changed while the ramdisk module is loaded. If your kernel is compiled with ramdisks built-in rather than as a module, then the only way to change the ramdisk size is to change the kernel parameters passed at boot.

If your kernel is compiled with ramdisks as a module (called rd), it is mostly possible to change ramdisk size, but it requires unloading the module, and then loading it again with different parameters:

rmmod rd
insmod rd rd_size=SIZE_IN_KB

Thanks zhangmaike,


I think I have my kernel compiled with ramdisks built in.


I guessed so because:-

[root@shakti myscripts]# modprobe rd FATAL: Module rd not found. You have new mail in /var/spool/mail/root [root@shakti myscripts]# insmod rd insmod: can't read 'rd': No such file or directory [root@bramha myscripts]#

So, I don't have any other choice except to reboot it, isn't it?

I have to try other way round then:-
I wanted to create a ramdisk for speeding up performance and minimize disk writes and reads.
So, for now I will have to :-

Create ramdisks(16 in no.) of 16 megs then have them all integrated into one raid 0 device so that it will act as one whole part of disk of 256 mb and restrict myself within this limit.


Thanks for your valuable help again

This link might be helpful to you: http://crazytoon.com/2007/06/01/ramd...s-rhel-fedora/

It does talk about rebooting but it shows how to setup different size in grub.

Did you notice the date on the question?