Some ideas for FreeBSD

Heiko Wundram (Beenic) wundram at
Fri Feb 8 17:22:43 UTC 2008

Am Freitag, 8. Februar 2008 17:54:03 schrieb millueradfa at
> Well, actually, these are file backed swap devices.
> You can do both file and memory backed devices. this
> allows you to have a swap file on the hard disk and
> mount it.

As I already wrote in another part of this thread: please explain to me why it 
should be faster to have a file backed md set up as swap than a dedicated 
swap partition (because there's at least two more levels of indirection 

I can clearly see the need for file backed swap in special cases (for example, 
where you need RAM desperately, for example for a compile, but cannot add 
another partition to a system), but no matter what, it will never be faster 
than a swap partition. And that was what the original poster of this 
sub-thread suggested (and as such, I took it that he was referring to 
memory-backed mds, because file-backed mds are never faster than "raw" access 
to a hard-disk).

So, I still stand by my first assessment: the idea to use an md as swap is 
stupid, at least from a performance standpoint.

Heiko Wundram
Product & Application Development

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