Date: Wed, 27 Oct 1999 12:38:04 -0700 (PDT) From: Matthew Dillon <dillon@apollo.backplane.com> To: "Ronald G. Minnich" <rminnich@lanl.gov> Cc: Ilia Chipitsine <ilia@cgilh.chel.su>, Chuck Youse <cyouse@paradox.nexuslabs.com>, questions@FreeBSD.ORG, hackers@FreeBSD.ORG Subject: Re: why FFS is THAT slower than EXT2 ? Message-ID: <199910271938.MAA35962@apollo.backplane.com> References: <Pine.SGI.4.10.9910271324180.671784-100000@acl.lanl.gov>
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:On Wed, 27 Oct 1999, Ilia Chipitsine wrote:
:> as far as I remember ext2 has some "counter". I used to use Linux and
:> it performed 'fsck' from time to time (even if fs was clearly unmounted).
:> that is a very good thing to have.
:
:And it's a good thing because ... well, maybe because it's not that
:reliable an FS. I actually can't see it as a good thing if you have a file
:system that doesn't need it.
:
:> I do not recall that FreeBSD did such thing.
:
:It might not have needed to. It never has in five years for me.
:
:The numbers are from my old job at sarnoff, see my web page ... for a
:while in 1997-99 we had "things go wrong" about once a month. Over the
:space of 18 months as "things went wrong" we found ourselves having to fix
:at least one Linux box each time. On average it was four.
:
:> I DID lose FFS even it was mounted "sync", not async.
:
:I guess I was lucky :-)
:
:anyway, I'll drop this thread, just trying to fill in some info.
:
:ron
To be fair, the counter gizmo for ext2fs was from a time many years ago
when ext2fs was not all that reliable. I believe ext2fs has gotten quite
a bit more reliable in the last year though. Also it is no longer
as simple as it was originally. It turns out there's a reason for
UFS/FFS's complexity. The linux crowd has similar problems with their
'simpler' swap and VM subsystems. But before people start smirking keep
in mind that linux is quite a bit farther ahead of us in the SMP
department.
When Kirk gets his softupdates/filesystem-checkmarking code working we
are going to be a step up from anything linux could hope to accomplish
in the filesystem arena because we will then be able to reliably dump,
checkmark, AND sanity-check the filesystem on a live (and busy) system.
-Matt
Matthew Dillon
<dillon@backplane.com>
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