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From: "Bert Huijben" <bert@qqmail.nl>
To: "'Philip Martin'" <philip.martin@wandisco.com>,
	=?utf-8?Q?'Branko_=C4=8Cibej'?= <brane@apache.org>
Cc: <dev@subversion.apache.org>
References: <87vba82pgl.fsf@wandisco.com> <561FD7F4.3090604@apache.org>
 <87k2qo2fpy.fsf@wandisco.com>
In-Reply-To: <87k2qo2fpy.fsf@wandisco.com>
Subject: RE: NFS performance regression in 1.9
Date: Thu, 15 Oct 2015 20:21:02 +0200
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> -----Original Message-----
> From: Philip Martin [mailto:philip.martin@wandisco.com]
> Sent: donderdag 15 oktober 2015 19:40
> To: Branko =C4=8Cibej <brane@apache.org>
> Cc: dev@subversion.apache.org
> Subject: Re: NFS performance regression in 1.9
>=20
> Branko =C4=8Cibej <brane@apache.org> writes:
>=20
> > And in another thread (on IRC, I think) we talked about not =
recommending
> > NFS because it's not reliable given our requirement for atomic =
renames.
>=20
> Lots of people, including Subversion developers, use working copies on
> NFS successfully.  It may not be perfect but it works well enough in
> lots of cases.  Pointing out potential pitfalls is fine, any sort of
> blanket ban would be odd.  Repositories on NFS might be more =
vulnerable.
>=20
> I think the usual problem for NFS rename is that while the underlying
> filesystem implements an atomic rename the mechanism that reports back
> to the client may fail.  Such an error may cause the client to exit =
with
> an error but the working copy itself is probably OK.
>=20
> All filesystems can have bugs.  How likely is NFS to fail for a =
typical
> user of Subversion working copies on NFS?  Is NFS less reliable than a
> local filesystem that uses LVM+mdadm+ZFS/BtrFS?  Is NFS less reliable
> than the firmware in a h/w RAID card?

I'm not able to answer all that, but I do know that your change will =
slow Subversion down on Samba shares as used from Windows systems with =
that flag. And once one user used it in that way it will stay slow =
because the journal mode is stored in the database.

I don't think just touching a working copy with a client should ever =
have such an effect on a working copy.

	Bert