Date: Thu, 05 Dec 2002 02:07:47 -0800 From: Terry Lambert <tlambert2@mindspring.com> To: Varshavchick Alexander <alex@metrocom.ru> Cc: freebsd-questions@FreeBSD.ORG, freebsd-hackers@FreeBSD.ORG Subject: Re: maxusers and random system freezes Message-ID: <3DEF2573.D8C66C11@mindspring.com> References: <Pine.GSO.4.33.0212051151540.7912-100000@apache.metrocom.ru>
next in thread | previous in thread | raw e-mail | index | archive | help
Varshavchick Alexander wrote: > On Wed, 4 Dec 2002, Terry Lambert wrote: > .... > > grep -B 7 KVA_ /sys/i386/conf/LINT > > Thanks a lot Terry, and will you please correct me if I'm wrong, so I > don't mess anything up on a production server? The kernel option in > question is KVA_PAGES, correct? Yes. > Because it's not defined in the custom > server's kernel then it's value default to 256 (FreeBSD 4.5-STABLE), which > makes the KVA space to occupy 1G. Then if I make KVA_PAGES=512 (KVA space > 2G), will it solve the problem for this particular server having 4G of > phisical memory, or must KVA_PAGES be 768 (KVA space 3G)? Have some other > options to be tuned besides KVA_PAGES? IMO, KVA need to be more than half of physical memory. But I tend to use a lot of mbufs and mbuf clusters in products I work on lately (mostly networking stuff). If you don't tune kernel memory usage up, then you may be able to get away with 2G. So: 2G might be OK, 3G would be more certain, given you are cranking some things up, in the config you posted, that make me think you will be eating more physical memory. If you follow the 1.5 rule, then you will have 6G of swap when you have 4G of physical RAM, and will definitely need to go for 3G of KVA space. Note, though: all space you add to KVA is subtracted from the process address space, so if you need big processes, sometimes you are better off with less physical RAM, and a larger user virtual address space. For other tuning information, see also "man tuning". -- Terry To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?3DEF2573.D8C66C11>