Date: Wed, 17 Mar 2021 02:31:30 +0000 From: Rick Macklem <rmacklem@uoguelph.ca> To: Alan Somers <asomers@freebsd.org> Cc: freebsd-fs <freebsd-fs@freebsd.org> Subject: Re: Understanding the vfs.nfsd.request_space* sysctls Message-ID: <YQXPR0101MB096871CFED5ADA41FC22713FDD6A9@YQXPR0101MB0968.CANPRD01.PROD.OUTLOOK.COM> In-Reply-To: <CAOtMX2ih9cLq3-Mw9xw3T9ovBiZ%2BY3PG82pN0s2eVusRooRF_g@mail.gmail.com> References: <CAOtMX2geF7Tv7VYc9WtK23a%2BnDzJzD2ehVKp94=xANjTA9S9Tg@mail.gmail.com> <YQXPR0101MB0968CD521F2A19F44488367ADD6B9@YQXPR0101MB0968.CANPRD01.PROD.OUTLOOK.COM>, <CAOtMX2ih9cLq3-Mw9xw3T9ovBiZ%2BY3PG82pN0s2eVusRooRF_g@mail.gmail.com>
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Alan Somers wrote:=0A= [stuff snipped]=0A= >That all makes sense. So having a high request_space_used basically just = means that >my storage is too slow.=0A= Since it appears that you have plenty of nfsd threads, that would imply=0A= that the bottleneck is probably the file system.=0A= (You might want to check that there is cpu available. ie. Some amount of=0A= idle cpu, just in case?)=0A= [more stuff snipped]=0A= >I've added an L2ARC since I sent that original email. We'll see how well = it works. I >expect it to take 48 hours before results are apparent.=0A= Others have tweaked something so that more of the arc is used for metadata.= =0A= [more stuff snipped]=0A= =0A= >Experimentally, I determined that 768 threads is sufficient. But your for= mula would >suggest > 2500, which is a lot of threads! I'll keep it in min= d if I ever reach 768, >though.=0A= 768 is probably plenty. My number would be an extreme upper bound.=0A= I did it because the default of 8 per cpu is very low (assumes a machine mo= stly=0A= doing other things).=0A= =0A= Good luck with it, rick=0A= =0A= =0A= rick=0A= =0A= -Alan=0A= _______________________________________________=0A= freebsd-fs@freebsd.org<mailto:freebsd-fs@freebsd.org> mailing list=0A= https://lists.freebsd.org/mailman/listinfo/freebsd-fs=0A= To unsubscribe, send any mail to "freebsd-fs-unsubscribe@freebsd.org<mailto= :freebsd-fs-unsubscribe@freebsd.org>"=0A= =0A=
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