Comments on: How to create a RAM disk http://boredzo.org/blog/archives/2006-05-09/how-to-create-a-ram-disk The personal weblog of Peter Hosey. Wed, 07 Jan 2009 02:55:34 +0000 http://wordpress.org/?v=2.6.5 By: Keith http://boredzo.org/blog/archives/2006-05-09/how-to-create-a-ram-disk#comment-201980 Keith Sat, 07 Jun 2008 22:16:02 +0000 http://boredzo.org/blog/archives/2006-05-09/how-to-create-a-ram-disk#comment-201980 Rollo, if you have performance issues due to disk but you have sufficient RAM to cache it all, one thing you can try is a script, either at startup of your application or running in the background, which reads everything into memory. I've been known to do the following to force the caching of a large directory: find /directory -type f -print0 | xargs -0 -Ifile dd if=file of=/dev/null bs=4096 And, while I haven't actually tried this yet (so far my RAMdisk needs don't exceed 1GB, let alone 2GB) ... Creating a RAID of RAMdisks should be possible. Just use level 0 or linear concatenation. With the latter you should be able to use any arbitrary number of RAMdisks of up to the 2GB size limit, to get the desired size. --Keith Rollo, if you have performance issues due to disk but you have sufficient RAM to cache it all, one thing you can try is a script, either at startup of your application or running in the background, which reads everything into memory. I've been known to do the following to force the caching of a large directory:

find /directory -type f -print0 | xargs -0 -Ifile dd if=file of=/dev/null bs=4096

And, while I haven't actually tried this yet (so far my RAMdisk needs don't exceed 1GB, let alone 2GB) ...

Creating a RAID of RAMdisks should be possible. Just use level 0 or linear concatenation. With the latter you should be able to use any arbitrary number of RAMdisks of up to the 2GB size limit, to get the desired size.

--Keith

]]> By: Rollo Carpenter http://boredzo.org/blog/archives/2006-05-09/how-to-create-a-ram-disk#comment-195711 Rollo Carpenter Wed, 14 May 2008 19:29:55 +0000 http://boredzo.org/blog/archives/2006-05-09/how-to-create-a-ram-disk#comment-195711 I'm glad to report that my Mac Pro's 28Gb are not wasted after all. It takes a day or two, but after a while my databases (for the jabberwacky.com conversational AI) find their way into some 'Active' and more 'Inactive' (but still re-used) memory, such that the HD access is vastly reduced, which was the whole point. So reports of RAM disks not being necessary are indeed true, as long as you're willing to wait a bit. I'm glad to report that my Mac Pro's 28Gb are not wasted after all. It takes a day or two, but after a while my databases (for the jabberwacky.com conversational AI) find their way into some 'Active' and more 'Inactive' (but still re-used) memory, such that the HD access is vastly reduced, which was the whole point. So reports of RAM disks not being necessary are indeed true, as long as you're willing to wait a bit.

]]> By: Peter Hosey http://boredzo.org/blog/archives/2006-05-09/how-to-create-a-ram-disk#comment-195207 Peter Hosey Mon, 12 May 2008 15:33:41 +0000 http://boredzo.org/blog/archives/2006-05-09/how-to-create-a-ram-disk#comment-195207 Rollo: Nope. As I said above: Even on Leopard, the disk images system doesn't support RAM disks larger than 2 GiB. I know of no other way to effect a RAM disk than through the disk images system. If I ever find one, I'll post about it and link to it from this post. Rollo: Nope. As I said above: Even on Leopard, the disk images system doesn't support RAM disks larger than 2 GiB. I know of no other way to effect a RAM disk than through the disk images system.

If I ever find one, I'll post about it and link to it from this post.

]]> By: Rollo Carpenter http://boredzo.org/blog/archives/2006-05-09/how-to-create-a-ram-disk#comment-195194 Rollo Carpenter Mon, 12 May 2008 14:58:31 +0000 http://boredzo.org/blog/archives/2006-05-09/how-to-create-a-ram-disk#comment-195194 Like Dale back in Nov 07, I need a very large RAM disk, and have not found a way. Have you come across anything? Thanks Rollo Like Dale back in Nov 07, I need a very large RAM disk, and have not found a way. Have you come across anything?

Thanks

Rollo

]]> By: Peter Hosey http://boredzo.org/blog/archives/2006-05-09/how-to-create-a-ram-disk#comment-142354 Peter Hosey Wed, 21 Nov 2007 02:31:38 +0000 http://boredzo.org/blog/archives/2006-05-09/how-to-create-a-ram-disk#comment-142354 Dale philpott: Not using this method. The disk-images system is still 32-bit (even on Leopard), so it can't allocate 4, 8, or 16 GiB of RAM. Dale philpott: Not using this method. The disk-images system is still 32-bit (even on Leopard), so it can't allocate 4, 8, or 16 GiB of RAM.

]]> By: Dale philpott http://boredzo.org/blog/archives/2006-05-09/how-to-create-a-ram-disk#comment-142332 Dale philpott Wed, 21 Nov 2007 00:33:36 +0000 http://boredzo.org/blog/archives/2006-05-09/how-to-create-a-ram-disk#comment-142332 Hi, Is there a way to create ram disks bigger than 2gb? if I try and create anything bigger then 2gb I get an error, hdiutil exited abnormally with status 1 I wanted to create a ram disk 4 8 or 16gb is size as I have 32gb ram Thanks Dale Hi, Is there a way to create ram disks bigger than 2gb? if I try and create anything bigger then 2gb I get an error, hdiutil exited abnormally with status 1

I wanted to create a ram disk 4 8 or 16gb is size as I have 32gb ram

Thanks

Dale

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