Date: Sat, 18 Nov 1995 18:21:55 -0500 (EST) From: Rashid Karimov <rashid@rk.ios.com> To: jimd@mistery.mcafee.com (Jim Dennis) Cc: questions@freebsd.org Subject: Re: MAXUSERS=64 -- kernel panics Message-ID: <199511182321.SAA27795@rk.ios.com> In-Reply-To: <199511180135.RAA07661@mistery.mcafee.com> from "Jim Dennis" at Nov 17, 95 05:35:55 pm
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HI there, > > > > Hey, > > I recently installed FreeBSD 2.0.5 to replace my overloaded > Linux box. We run an ftp site that almost as popular as > Walnut Creek's (roughly 400,000 file transfers per month). Do _not go with 2.0.5 - it is very unstable ... I run 2.10 Stable on 7 _big servers ( 4000 -10000 accounts each) - no problemo. I have maxusers=128 usually and just ignore :) the message about maxusers being over 64. Didn't have much time to dive into the sources to see why does it complain at all. > > Naturally I found that the generic kernel would run out of > file handles almost immediately (5 min. max.) that was > at 24 incoming sessions. Besides I certainly planned on > rebuilding the kernel anyway. So I config'd to 128 -- > it complained that this was > 64, so I brought it down > to 64 and rebuilt. > > Stop reading if you've heard this one before..... > > Ahh -- this must be news then -- she reboots! The 2.0 kernel > (which I had tried first) would wait ten minutes (getting upto > 70 ftp sessions or so) and then panic. 2.0.5 had the grace to > refrain from lulling me into a false sense of security by > dying immediately. Hmmmm. it should complain loudly about being unable to open new file(s) because of lack of resources - but it definitely shouldn't panic because of it > > It was a simple matter to reboot on the generic kernel, > 'ifconfig de0 down' and build one with MAXUSERS set to > 32. That was stable but would run out of file handles > at ~95+ users (under a half hour). So I built her again > with a setting of 63 and brought her back up. I've been > monitoring her for a week now with a cron job to mail me > ftpcount's every hour and an entry in rc.local to mail me > a dmesg on every reboot (root is .forwarded to another box > inside -- from which I'm mailing this). > > There have been no more reboots. The ftpcount has been > averaging 150 and the I wrote a test to start 200 concurrent > processes (while 50 users were in from outside) at which > she didn't even blink. > > So, moral of that story is -- don't set MAXUSERS to 64. > This is a Pentium 90 with 64Mb of RAM, NCR PCI SCSI and > a DEC PCI ethernet (only about a Gig online). Obviously weird :)) Rashid
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