Date: Fri, 21 Sep 2007 11:37:53 -0700 From: Jeremy Chadwick <koitsu@FreeBSD.org> To: freebsd-current@freebsd.org Subject: dump(8) and "Approaching the limit on PV entries" Message-ID: <20070921183753.GA68493@eos.sc1.parodius.com>
next in thread | raw e-mail | index | archive | help
I'm new to the present -CURRENT, so go easy on me. :-) I run periodic backups on my LAN at home, and since switching from RELENG_6 I've begun to see this kernel message emit when dump(8) runs with a dump level of 0 on one specific filesystem. Incrementals, at least so far, haven't caused this. Sep 20 03:09:58 icarus kernel: Approaching the limit on PV entries, consider increasing tunables vm.pmap.shpgperproc or vm.pmap.pv_entry_max The filesystem in question is a GEOM stripe class consisting of two disk members, ad4 and ad6. Sector sizes are default (512 bytes). I chose a stripe size of 256KB. Filesystem 1024-blocks Used Avail Capacity Mounted on /dev/stripe/st0 946141880 80111848 790338688 9% /storage Additional tunefs parameters were used as well; everything is default except: tunefs: maximum blocks per file in a cylinder group: (-e) 16384 tunefs: average file size: (-f) 65536 tunefs: average number of files in a directory: (-s) 256 How I'm doing backups: /sbin/dump -0 -a -h0 -u -C16 -L -f- /storage | dd of=/backups/storage.0.dump I haven't tried removing the use of -C16 (16MB cache) to see if that makes a difference. I assumed vm.pmap.shpgperproc adjusted the number of shared VM pages available per process, so I opted to increase that from 200 (default) to 1000 using loader.conf and reboot. However, I still get the message, which indicates I may need to apply further tuning. But rather than blindly increase numbers, I thought I'd ask others for recommendations or clues as to what's going on. Thanks for educating me. :-) -- | Jeremy Chadwick jdc at parodius.com | | Parodius Networking http://www.parodius.com/ | | UNIX Systems Administrator Mountain View, CA, USA | | Making life hard for others since 1977. PGP: 4BD6C0CB |
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?20070921183753.GA68493>