g_vfs write error = 28, bad memory?

[Ian Smith]

On Sat, 01 Sep 2007 19:34:41 +0200 Kris Kennaway <kris at FreeBSD.org> wrote:
 > Per olof Ljungmark wrote:
 > > Kris Kennaway wrote:
 > >> Per olof Ljungmark wrote:
 > >>> Kris Kennaway wrote:
 > >>>> Per olof Ljungmark wrote:
 > >>>>> I use a memory file system for some tmp files and last night I saw 
 > >>>>> this, followed by a reboot. Bad memory? 6-STABLE from April..
 > >>>>>
 > >>>>> foo-bar kernel: g_vfs_done():md0[WRITE(offset=259244032, 
 > >>>>> length=131072)]error = 28
 > >>>>> foo-bar kernel: g_vfs_done():md0[WRITE(offset=259375104, 
 > >>>>> length=131072)]error = 28
 > >>>>> [ten more lines...]
 > >>>>> [reboot]
 > >>>>>
 > >>>>> Thanks,
 > >>>>
 > >>>> #define ENOSPC          28              /* No space left on device */
 > >>>>
 > >>>> You are probably (incorrectly) using a malloc backed disk.  Use swap 
 > >>>> backing and you won't panic when memory is low.
 > >>>
 > >>> Yes, sounds likely, thanks. One more question then, where is the md 
 > >>> information stored through a reboot? I did not edit rc.conf or fstab 
 > >>> or kernel config but still /dev/md0 came back up. Hmmm.
 > >>
 > >> It's not, unless something is explicitly creating it each time you 
 > >> boot.  Perhaps you are using a rc.conf setting that creates a md /tmp.
 > > 
 > > Indeed, here it was:
 > > 
 > > amavisd_enable="YES"
 > > amavisd_ram="512m"
 > > 
 > > and the line in rc.d/amavisd
 > > mdmfs -M -s ${amavisd_ram} -w vscan:vscan md /var/amavis/tmp || true
 > > for some reason creates a malloc based mfs
 > > 
 > > Perhaps I should check this with the maintainer...
 > > 
 > > 
 > 
 > Yes, malloc backing for md should be used in almost no situations.

Am I right in thinking such situations would then be limited to diskless
/ flashdisk / embedded systems having no swap?  Seems obvious, but ..

Cheers, Ian