It's on the mds server (this is in 1.4.x) /proc/fs/lustre/mds/.../atime_diff.
Lundgren, Andrew wrote: > In my test cluster, I tried mounting with the noatime parameter. It was not > supported for the client or the OSTs. > > You mention the largest performance gain below, did you change that yourself, > or did lustre change that with the install? If you changed it, how high did > you set it? > > For our web server, we really don't care when the files were read, they will > be there anyway. The atime info is not valuable to us at all, the writes are > just overhead. > > Thanks! > > -- > Andrew > > >> -----Original Message----- >> From: [EMAIL PROTECTED] >> [mailto:[EMAIL PROTECTED] On Behalf Of >> Adam Cassar >> Sent: Tuesday, April 29, 2008 8:11 PM >> To: '[EMAIL PROTECTED]' >> Subject: Re: [Lustre-discuss] lustre and noatime option >> >> >> The problem isn't with the RPC - its with the additional disk writes. >> >> The single lrgest metadata performance gain we achieved was >> by changing >> the atime_diff parameter in /proc >> >> >> Brian J. Murrell wrote: >> >>> On Tue, 2008-04-29 at 13:09 -0600, Lundgren, Andrew wrote: >>> >>> >>>> I don't need to know the last access time on my files. I looked >>>> though the manual, but didn't find a reference to noatime. Does >>>> lustre use that setting? (on the cl >>>> >>>> -- >>>> >>>> Adam Cassar >>>> ICT Manager >>>> NetRegistry >>>> ------------------------------------------------------- >>>> o: 02 9699 6099 >>>> f: 02 9699 6088 >>>> d: 02 9641 8609 >>>> ------------------------------------------------------- >>>> >>>> Netregistry Pty Ltd >>>> www.netregistry.com.au >>>> PO Box 270 Broadway, NSW 2007 >>>> tel: +61 2 9699 6099 fax: +61 2 9699 608 >>>> ient and/or server) >>>> >>>> >>> I don't believe it does because... >>> >>> >>> >>>> On a file system that is read heavily, I would expect to see a >>>> performance improvement by using that. Is that true for lustre as >>>> well? >>>> >>>> >>> Lustre already handles atime in a pretty efficient manner. >>> >> Rather than >> >>> disable it completely we update it "lazily". What that >>> >> means is that >> >>> rather than sending immediate and explicit RPCs to update >>> >> the atime we >> >>> will delay sending them (for up to 5 seconds, tunable IIRC) >>> >> and try to >> >>> send atime updates "piggybacked" with other RPC traffic. >>> >>> b. >>> >>> >>> >>> >> -------------------------------------------------------------- >> ---------- >> >>> _______________________________________________ >>> Lustre-discuss mailing list >>> [email protected] >>> http://lists.lustre.org/mailman/listinfo/lustre-discuss >>> >>> >> -- >> >> Adam Cassar >> ICT Manager >> NetRegistry >> ------------------------------------------------------- >> o: 02 9699 6099 >> f: 02 9699 6088 >> d: 02 9641 8609 >> ------------------------------------------------------- >> >> Netregistry Pty Ltd >> www.netregistry.com.au >> PO Box 270 Broadway, NSW 2007 >> tel: +61 2 9699 6099 fax: +61 2 9699 608 >> >> _______________________________________________ >> Lustre-discuss mailing list >> [email protected] >> http://lists.lustre.org/mailman/listinfo/lustre-discuss >> >> > _______________________________________________ > Lustre-discuss mailing list > [email protected] > http://lists.lustre.org/mailman/listinfo/lustre-discuss > > -- Adam Cassar ICT Manager NetRegistry ------------------------------------------------------- o: 02 9699 6099 f: 02 9699 6088 d: 02 9641 8609 ------------------------------------------------------- Netregistry Pty Ltd www.netregistry.com.au PO Box 270 Broadway, NSW 2007 tel: +61 2 9699 6099 fax: +61 2 9699 608 _______________________________________________ Lustre-discuss mailing list [email protected] http://lists.lustre.org/mailman/listinfo/lustre-discuss
