On Wed, Sep 09, 2009 at 04:46:56PM +0100, Daniel Bye wrote: > On Wed, Sep 09, 2009 at 10:59:23AM -0400, Jerry McAllister wrote: > > On Wed, Sep 09, 2009 at 11:57:07AM +0100, Daniel Bye wrote: > > > > > On Tue, Sep 08, 2009 at 07:52:59PM -0400, Jerry McAllister wrote: > > > > On Tue, Sep 08, 2009 at 04:51:20PM -0500, Peter Steele wrote: > > > > > > > > > Are there any advantages to using mdconfig and creating a virtual > > > > > disk for swap space as opposed to having a designated swap partition? > > > > > For example, I could do something like this: > > > > > > > > Unless I am missing something basic here, it seems like a bad idea to > > > > me - to carve out and use up some memory to use as extra storage for > > > > processes that need more memory that you have taken away to give to > > > > swap. > > > > That is self defeating. > > > > > > > > In addition, one use of swap is to write dumps to if there is a crash. > > > > If you put it in memory, it is gone when you reboot. > > > > > > He's talking about using a swap file, rather than a dedicated partition > > > on > > > the disk, not in RAM! Although it is slightly slower, as Chuck has > > > already > > > pointed out, it might, in certain circumstances, be a somewhat more > > > convenient solution than repartitioning/reinstalling the whole system. > > > > > > And as RW has said, the facility already exists and can be enabled with a > > > couple of knobs in /etc/rc.conf. > > > > I understand using a file and making it in to swapspace. I have used that > > a couple of times when I needed to add some swap space temporarily. But > > isn't the command he is trying to use (mdconfig) for creating a memory > > filesystem - eg use a chunk of memory and make a file from it (then use it > > for swap or whatever)? That is in RAM. > > No, with the -t vnode and -f <filename> options, he'd actually be creating > a file-backed memory disk. The terminology can be a little confusing, but > in this instance the file wouldn't be loaded into RAM, but would instead > be treated as any other disk-like device. It's exactly the same approach > as used by /etc/rc.d/addswap, which gets its configuration from $swapfile > set in /etc/rc.conf.
I see that now, but it seems like the long way around to get to what you get with a swapon. Oh well. ////jerry > > Dan > > -- > Daniel Bye > _ > ASCII ribbon campaign ( ) > - against HTML, vCards and X > - proprietary attachments in e-mail / \ _______________________________________________ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to "freebsd-questions-unsubscr...@freebsd.org"
