Also beware there are 2 different linux NFS "async" settings. A client side setting (mount -o async), which still cases sync on file close() -- and a server (knfs) side setting (/etc/exports) that violates NFS protocol and returns requests before data has hit stable storage.
-jf On Wed, Oct 17, 2018 at 9:41 AM Tomer Perry <[email protected]> wrote: > Hi, > > Without going into to much details, AFAIR, Ontap integrate NVRAM into the > NFS write cache ( as it was developed as a NAS product). > Ontap is using the STABLE bit which kind of tell the client "hey, I have > no write cache at all, everything is written to stable storage - thus, > don't bother with commits ( sync) commands - they are meaningless". > > > Regards, > > Tomer Perry > Scalable I/O Development (Spectrum Scale) > email: [email protected] > 1 Azrieli Center, Tel Aviv 67021, Israel > Global Tel: +1 720 3422758 > Israel Tel: +972 3 9188625 > Mobile: +972 52 2554625 > > > > > From: "Keigo Matsubara" <[email protected]> > To: gpfsug main discussion list <[email protected]> > Date: 17/10/2018 16:35 > Subject: Re: [gpfsug-discuss] Preliminary conclusion: single > client, single thread, small files - native Scale vs NFS > Sent by: [email protected] > ------------------------------ > > > > I also wonder how many products actually exploit NFS async mode to improve > I/O performance by sacrificing the file system consistency risk: > > [email protected] wrote on 2018/10/17 22:26:52: > > Using this option usually improves performance, but at > > the cost that an unclean server restart (i.e. a crash) can cause > > data to be lost or corrupted." > > For instance, NetApp, at the very least FAS 3220 running Data OnTap > 8.1.2p4 7-mode which I tested with, would forcibly *promote* async mode to > sync mode. > Promoting means even if NFS client requests async mount mode, the NFS > server ignores and allows only sync mount mode. > > Best Regards, > --- > Keigo Matsubara, Storage Solutions Client Technical Specialist, IBM Japan > TEL: +81-50-3150-0595, T/L: 6205-0595 > _______________________________________________ > gpfsug-discuss mailing list > gpfsug-discuss at spectrumscale.org > http://gpfsug.org/mailman/listinfo/gpfsug-discuss > > > > _______________________________________________ > gpfsug-discuss mailing list > gpfsug-discuss at spectrumscale.org > http://gpfsug.org/mailman/listinfo/gpfsug-discuss >
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