Date: Sat, 9 Oct 2021 16:09:52 +0000 From: Rick Macklem <rmacklem@uoguelph.ca> To: Felix Palmen <felix@palmen-it.de>, "freebsd-current@freebsd.org" <freebsd-current@freebsd.org> Subject: Re: Writing large build logs to NFS extremely slow? Message-ID: <YQXPR0101MB0968CA670A7AD47437D64E5FDDB39@YQXPR0101MB0968.CANPRD01.PROD.OUTLOOK.COM> In-Reply-To: <20211009155033.fckg4i7zqo4yt2te@nexus.home.palmen-it.de> References: <20211007021643.bwglyvrswk2nm3fl@nexus.home.palmen-it.de> <CAOgwaMsLTWaMddx1HPY0eiY4t-12x-bEiZmhUpFsuEqkNhM27w@mail.gmail.com> <20211009141852.3cmjh7tysnehum7b@nexus.home.palmen-it.de> <YQXPR0101MB096832C878E88DF877B39DB8DDB39@YQXPR0101MB0968.CANPRD01.PROD.OUTLOOK.COM> <20211009155033.fckg4i7zqo4yt2te@nexus.home.palmen-it.de>
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Felix Palmen wrote:=0A= >* Rick Macklem <rmacklem@uoguelph.ca> [20211009 15:35]:=0A= >> Felix Palmen wrote:=0A= >> Assuming your NFS performance is acceptable for other things and it=0A= >> is only this log file that is a problem, then I doubt there is much you= =0A= >> can do to improve it.=0A= >=0A= >Yes, that's the only problem I found so far=85=0A= Another thing you could try is turning off synchronous writing at the NFS s= erver.=0A= # sysctl vfs.nfsd.async=3D1=0A= and "sync=3Ddisabled" for ZFS if it is a ZFS file system that is exported.= =0A= =0A= However, BE FORWARNED:=0A= Doing so violates the NFS RFCs because it can result is data loss/corrupted= files=0A= that are being written when the NFS server crashes/reboots.=0A= Only do it if the data being written to the NFS server is not particularly = important stuff.=0A= =0A= rick=0A= =0A= > --> Append (as in O_APPEND opens) are a poor case for NFS, since there=0A= > is no append write in NFS. To approximate append write, it must flu= sh=0A= > all dirty data to the server, do a Getattr to find out the file's c= urrent=0A= > size and then do the write (over and over and over again).=0A= =0A= Ok, thanks for the insight here! So maybe, I could have a look at=0A= poudriere's code? If I understand you correctly, keeping the file open=0A= and just issuing more write() calls wouldn't trigger that problem?=0A= =0A= > You could try the "nocto" mount option, which might help, if the log file= =0A= > is being re-opened many times, but I doubt it will help.=0A= =0A= Well, I take any suggestion, so will try that as well and report back,=0A= thanks again!=0A= =0A= Side note, please don't CC/To me, I'm subscribed the list ;)=0A= =0A= --=0A= Dipl.-Inform. Felix Palmen <felix@palmen-it.de> ,.//..........=0A= {web} http://palmen-it.de {jabber} [see email] ,//palmen-it.de=0A= {pgp public key} http://palmen-it.de/pub.txt // """""""""""=0A= {pgp fingerprint} A891 3D55 5F2E 3A74 3965 B997 3EF2 8B0A BC02 DA2A=0A=
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