On Thu, Apr 11, 2024 at 06:15:14PM +0200, Otto Moerbeek wrote:
> On Thu, Apr 11, 2024 at 05:29:14PM +0200, Otto Moerbeek wrote:
> 
> > On Thu, Apr 11, 2024 at 05:20:24PM +0200, Otto Moerbeek wrote:
> > 
> > > On Thu, Apr 11, 2024 at 05:08:01PM +0200, Federico Giannici wrote:
> > > 
> > > > On 4/11/24 16:15, Claudio Jeker wrote:
> > > > > On Thu, Apr 11, 2024 at 03:36:29PM +0200, Federico Giannici wrote:
> > > > > > On 4/11/24 14:12, Nick Holland wrote:
> > > > > > > On 4/11/24 05:47, Federico Giannici wrote:
> > > > > > > > We have a server with A LOT of files in some directories (an 
> > > > > > > > email
> > > > > > > > server in maildir format).
> > > > > > > > 
> > > > > > > > Since we upgraded from OpenBSD amd64 7.3 to 7.5 (passing 
> > > > > > > > through 7.4) it
> > > > > > > > became very very very slow to access these large directories!
> > > > > > > ,,,
> > > > > > > You may be being bitten by the removal of softdeps (soft updates)
> > > > > > > in 7.4 more than the availability of a knob to twist.  This was a
> > > > > > > huge hit for some things -- I had one backup job go from a couple
> > > > > > > hours to eight or so hours.  However, it turned out that increase
> > > > > > > in time has not inconvenienced me at all, and some random lockups
> > > > > > > related to softdeps have gone away.  Overall, win for me (the
> > > > > > > fscks after a lockup took hours, too, not to mention all the time
> > > > > > > and effort spent replacing part after part assuming it was a HW
> > > > > > > issue).
> > > > > > > 
> > > > > > > As I understand it...there were known (known unknown?) bugs in the
> > > > > > > softdep code, the code was ugly, and it made it difficult to
> > > > > > > actually improve the code.
> > > > > > 
> > > > > > No, we knew that softdeps were being deprecated and we removed from
> > > > > > everywhere some time ago. It must be something else.
> > > > > > 
> > > > > > Anyway, it's strange that dirhash parameters has being changed and 
> > > > > > removed
> > > > > > without any mention...
> > > > > 
> > > > > It was not (this is on -current amd64):
> > > > > vfs.ffs.dirhash_dirsize=2560
> > > > > vfs.ffs.dirhash_maxmem=5242880
> > > > > vfs.ffs.dirhash_mem=4832510
> > > > > 
> > > > > Are you sure your kernel and userland are in sync?
> > > > 
> > > > Well, I followed the prescribed procedure (I'm using OpenBSD since... 
> > > > about
> > > > 20 years).
> > > > 
> > > > In EVERY machine upgraded to 7.5 now I have something like this:
> > > > 
> > > > Elrond:/home/giannici$ sysctl vfs.ffs
> > > > 
> > > > 
> > > > 
> > > > vfs.ffs.dirhash_maxmem=2560
> > > > vfs.ffs.dirhash_mem=5242880
> > > > 
> > > > Elrond:/home/giannici$ uname -a
> > > > 
> > > > 
> > > > 
> > > > OpenBSD Elrond.neomedia.it 7.5 GENERIC.MP#82 amd64
> > > > 
> > > > 
> > > > So, I'm the only one?
> > > > 
> > > > Thanks.
> > > > 
> > > 
> > > I suspect 
> > > 
> > > In 
> > > https://cvsweb.openbsd.org/cgi-bin/cvsweb/src/sys/ufs/ffs/ffs_exatern.h.diff?r1=1.45&r2=1.46&f=h
> > > 
> > > The max_softdeps entry in ffs_extern.h should have been replace by a
> > > { 0, 0 }
> > > 
> > > instead of being removed.
> > > 
> > >   -Otto
> > > 
> > 
> > Yes, that fixes it for me:
> > 
> > $ sysctl vfs.ffs
> > vfs.ffs.dirhash_dirsize=2560
> > vfs.ffs.dirhash_maxmem=5242880
> > vfs.ffs.dirhash_mem=767359
> > $
> > 
> 
> to elaborate a bit: the vfs.ffs.dirhash_maxmem enty was actually
> showing the value of the vfs.ffs.dirhash_dirsize entry. Trying to set the
> vfs.ffs.dirhash_maxmem entry would result into setting the
> vfs.ffs.dirhash_dirsize entry, which effectively disables dirhash if
> yon set it to a high value.
> 
> It remains a mystery why Claudio is seeing the correct values... you'd
> almost think he uses an old sysctl binary, or his tree is out of sync
> somehow. 
> 

My bad I ran the command on a system that was still running 7.4 without
realizing that.

-- 
:wq Claudio

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