ramdisk info

[vodkadrinker]

Please can someone point me in the right direction for ramdisks, more about how they work than how to create them.

 

[DukeSSD]

http://publib.boulder.ibm.com/infoc...=/com.ibm.aix.cmds/doc/aixcmds3/mkramdisk.htm

 

[vodkadrinker]

That pretty much what I have found I was more after how it works.

 

[hfaix]

Interesting concept. I've never come across this before. Are the benefits as obvious as they seem (faster I/O to RAM than to disk?)....or is this just a crazy way of creating more space? Does anyone do this?

 

[p5wizard]

Well, you have actually... Every time you boot an AIX system, I believe ;-)


HTH,

p5wizard

 

[hfaix]

Good Point

 

[RodKnowlton]

The reason most people haven't come across this, at least in AIX, is that with modern virtual memory management and file caching there isn't much benefit (if any) to be had in using a ramdisk.

You would only use one for files that a.) you aren't worried about losing and b.) are frequently accessed. Not a lot of files meet both criteria, and those that do will end up cached anyway.

- Rod


IBM Certified Advanced Technical Expert pSeries and AIX 5L
CompTIA Linux+
CompTIA Security+

A Simple Code for Posting on the Web

 

[p5wizard]

That was my other thought: why use a ramdisk and worry about loading it at boot time, offloading it to disk at shutdown, when you can have a well tuned I/O system with memory mapped file I/O which basically has all the benefits of a ramdisk and none of the drawbacks...

Reason AIX uses it at boot is it needs a filesystem in order to build a micro-system in order to load the necessary device drivers and fire up IO subsystems to access the filesystem on external devices.


HTH,

p5wizard

 

[vodkadrinker]

Thanks for your posts, this also explains probably why I am not finding more info.

VD