Date: Wed, 09 Nov 2011 15:20:05 +0100 From: Ivan Voras <ivoras@freebsd.org> To: freebsd-fs@freebsd.org Subject: Re: [RFC] Should vfs.nfsrv.async be implemented for new NFS server? Message-ID: <j9e26l$ht8$1@dough.gmane.org> In-Reply-To: <1558351773.1229453.1320542285788.JavaMail.root@erie.cs.uoguelph.ca> References: <1558351773.1229453.1320542285788.JavaMail.root@erie.cs.uoguelph.ca>
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[-- Attachment #1 --] On 06/11/2011 02:18, Rick Macklem wrote: > Hi, > > Josh Paetzel pointed out that vfs.nfsrv.async doesn't exist > for the new NFS server. > > I don't think I had spotted this before, but when I looked I > saw that, when vfs.nfsrv.async is set non-zero in the old server, > it returns FILESYNC (which means the write has been committed to > non-volatile storage) even when it hasn't actually done that. Do I understand this correctly: the server normally (for async=0) does a fsync after any writes and returns FILESYNC status to the client? This seems too extreme... doesn't NFSv4 have its own fsync()-like RPC that does that manually? If it does, then I don't think there are any differences between doing a write() on a local file system with e.g. soft-updates enabled and doing a write on a NFS file system - in both cases, no data is even remotely guaranteed to survive a crash unless a fsync (or equivalent operation) was issued. On 06/11/2011 17:25, Josh Paetzel wrote: > In 8.x, setting the async sysctl was the difference between 80-100MB/sec > and 800 MB/sec (Yes, MegaBytes!) using a variety of different clients, Yup, this is in any case too big not to add the async mode. [-- Attachment #2 --] -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.18 (FreeBSD) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org/ iEYEARECAAYFAk66jBUACgkQldnAQVacBchbtwCgk7wbUqaY08vOSwU+OYYvWuqr XtMAoJWCJgg2AkWcrrQ8TyEpHt1JAR99 =LcwZ -----END PGP SIGNATURE-----
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