Re: Summary: Moving /tmp to tmpfs makes it useless
On Sat, Jun 23, 2012 at 06:00:15PM +0300, Touko Korpela wrote:
> Tollef Fog Heen wrote:
> > > On Sun, Jun 10, 2012 at 07:46:57PM +0200, Stephan Seitz wrote:
> > > > On Sun, Jun 10, 2012 at 07:12:11PM +0200, Tollef Fog Heen wrote:
> > > > >]] Stephan Seitz
> > > > >>Will Wheezy support SSDs out of the box with all trimming functions,
> > > > >>even if your SSD partition is using LUKS and LVM?
> > > > >Depends on what you mean by out of the box. I suspect you still need
> > > > >to
> > > > >turn on discard support (since it has security implications). It does
> > > > >not require extra packages or patches.
> > > > Well, nice to hear, but I thought, discard was needed in all layers,
> > > > so in my example in LUKS, then in LVM and then in the filesystem. Or
> > > > is his only a function you activate via hdparm?
> > >
> > > It's available in all layers, but as Tollef said it's manual. (In crypttab
> > > most
> > > likely, because that's commonly the lowest layer.)
> > You need to enable it in all layers (fstab, crypttab, lvm.conf), yes.
This was what I read elsewhere too.
> For now you shouldn't use discard option with SSDs, it's bad for
> performance. Better is to run fstrim periodically.
Could you care to give us pointer to the rational behind your assertion?