"generally reliable" HAHAHAHAHA
On Thu, Jul 23, 2015 at 09:31:59PM -0400, Michael McConville wrote: > On Thu, Jul 23, 2015 at 06:49:55PM -0600, Theo de Raadt wrote: > > > There was a great discussion about softdep recently: > > > > > > https://marc.info/?t=142164016900001&r=1&w=2 > > > > > > It needs extra memory, so the FAQ warns against its use on really > > > old architectures. > > > > > > tedu@ described the two main deterrents: > > > > > > https://marc.info/?l=openbsd-misc&m=142294185000751&w=2 > > > > > > Might it be worth making default for AMD64? The performance gain is > > > big in many cases. > > > > > There is no way this diff is going in. > > > > When softdep is 100% reliable, then we can talk. > > > Enabling it prematurely is ridiculous. Considering the defects > > are clearly described as lockups, disk space corruption -- with > > such a suggestion I must ask --who's side are you on?? > > The first issue that Ted mentions is just characteristic of soft > updates, right? He discusses it more here: > > https://marc.info/?l=openbsd-misc&m=142250784228719&w=2 > > The second one sounds specific to implementation bugs. I didn't know how > well those had been combed out. > > Here's another diff. Someone who knows more than I do about soft updates > can probably word it better. > > > Index: faq/faq14.html > =================================================================== > RCS file: /cvs/www/faq/faq14.html,v > retrieving revision 1.253 > diff -u -p -r1.253 faq14.html > --- faq/faq14.html 2 Jul 2015 05:49:04 -0000 1.253 > +++ faq/faq14.html 24 Jul 2015 01:25:03 -0000 > @@ -913,6 +913,12 @@ with soft updates. > </pre></blockquote> > > <p> > +While soft updates are widely used and generally reliable, they can worsen > the > +impact of I/O errors. Also, if many small files are quickly modified on a > slow > +disk, the fileystem may struggle to cope with the accumulating deferred > +updates. > + > +<p> > Note to sparc users: Do not enable soft updates on sun4 or sun4c > machines. These architectures support only a very limited amount of > kernel memory and cannot use this feature. However, sun4m machines are > Index: faq/obsd-faq.txt > =================================================================== > RCS file: /cvs/www/faq/obsd-faq.txt,v > retrieving revision 1.39 > diff -u -p -r1.39 obsd-faq.txt > --- faq/obsd-faq.txt 5 Jun 2015 12:04:13 -0000 1.39 > +++ faq/obsd-faq.txt 24 Jul 2015 01:25:04 -0000 > @@ -11531,6 +11531,11 @@ that has one partition sd0a that we wish > > /dev/sd0a / ffs rw,softdep 1 1 > > +While soft updates are widely used and generally reliable, they can worsen > the > +impact of I/O errors. Also, if many small files are quickly modified on a > slow > +disk, the fileystem may struggle to cope with the accumulating deferred > +updates. > + > Note to sparc users: Do not enable soft updates on sun4 or sun4c machines. > These architectures support only a very limited amount of kernel memory and > cannot use this feature. However, sun4m machines are fine. >
