>---------- Forwarded message ---------- >Date: Mon, 21 Sep 1998 18:47:38 -0500 (CDT) >From: "Kurt D. Bollacker" <[EMAIL PROTECTED]> >Subject: RAMDISK for linux? > > >I'm going to go nuts. Without rewriting tons of code, I need to speed my >simulations up my moving file accesses to a ramdisk. However, The linux >HOWTO's only talk about setting up small ramdisks for the booting process. >When I create a 128MB ramdisk using that procedure, the kernel becomes >unstable. Yuk! Any suggestions? Has anybody done this? here's an alternative suggestion: mount the partition you have your work files on with -o noatime (may require a very recent kernel + a kernel rebuild with the noatime option enabled somewhere...not sure about that), and you'll basically be working on a ramdisk anyway. linux is *very* good at caching file contents in ram, and does so automatically when there is spare memory. so much so that the kernel mailing list oftentimes tells people in your situation to skip the ramdisk because linux is like a smart ramdisk all by itself. the noatime option means that the filesystem won't be touched when you read-only access a file, as unix normally updates the Access TIME on files you use, leading to oft-times useless disk activity. some things like biff are broken by it so it's not generally advisable to mount all your fs'es that way. obviously this isn't a huge win if you're constantly changing the contents of large files as the disk will still be written with the changes, slowing things down. but try the following to see how effective the caching strategy on linux is: (with a local huge file): time cat file > /dev/null time cat file > /dev/null and note show short the second cat is! also note the lack of disk grinding altho it will still 'tick' as it updates the atime. HTH. --------------------------------------------------------------------------- Send administrative requests to [EMAIL PROTECTED]
