Date: Sun, 19 May 2019 02:47:10 +0000 From: Rick Macklem <rmacklem@uoguelph.ca> To: Alan Somers <asomers@freebsd.org> Cc: "freebsd-current@FreeBSD.org" <freebsd-current@FreeBSD.org> Subject: Re: RFC w.r.t. toggling debugging on/off for mountd via a signal Message-ID: <YQXPR0101MB205583575B42875DD298FA65DD050@YQXPR0101MB2055.CANPRD01.PROD.OUTLOOK.COM> In-Reply-To: <CAOtMX2gXdjf2NhtU5Jt%2BMGg3zcONx_Gyun%2B2thy2rDYDt3FugQ@mail.gmail.com> References: <YQXPR0101MB2055B12D1AB31D4F70AF2480DD050@YQXPR0101MB2055.CANPRD01.PROD.OUTLOOK.COM>, <CAOtMX2gXdjf2NhtU5Jt%2BMGg3zcONx_Gyun%2B2thy2rDYDt3FugQ@mail.gmail.com>
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Alan Somers wrote: >On Sat, May 18, 2019 at 7:59 PM Rick Macklem <rmacklem@uoguelph.ca> wrote: >> >> Hi, >> >> I've been working with Peter Errikson on a patch for mountd that adds a = new option >> for incremental updating of exports. This seems to be helping a lot w.r.= t. performance >> on an NFS server with lots (10000+) of exported file systems. >> >> I have debug syslog() calls in the code, which I/Peter think would be wo= rth keeping >> in the production code in case someone runs into problems with this new = option. >> >> As such, I'd like to have the code compiled in by default (not only if D= EBUG is defined, >> as mountd.c has now). I also was thinking it would be nice if the daemon= didn't need >> to be restarted to enable/disable the debugging output, since that break= s NFS >> mounting during the restart. >> >> So, I was thinking of having the debugging output toggled on/off via SIG= USR1. >> >> What do you think of this idea? >> Any other/better ways to do this? >> Also, would LOG_DAEMON and LOG_DEBUG sound like the correct facility and >> priority for theses syslog() calls? >> >> Thanks in advance for any comments, rick > >If the debug messages aren't so verbose that they'll slow down >syslogd, then you can just leave them enabled all the time. syslogd >will filter them. However, if they're super-verbose then SIGUSR1 >sounds reasonable. I can't think of another daemon with runtime >selectable logging verbosity like that. Yes, these are pretty chatty. 5-10 lines for each entry in an exports file. Multiply that times the number of entries. (Peter's servers are between 200= 00 to 72000+ file systems. Not sure if he has multiple entries/file system.) To give you a clue, without this patch, it can take 20sec->over 1min to rel= oad them when mountd gets a SIGHUP. It's just that the export file handling code is pretty convoluted, so I thi= nk the patch is ok, but I won't be too surprised if someone finds a problem. rick
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