Re: [Soekris] Smallest possible MFS /dev on OpenBSD
On 2008/01/21 12:18, Jean-Yves Boisiaud wrote: there is no typo, but I forgot to tell that the system I use was old : uname -a OpenBSD xx 3.8 GENERIC#138 i386 and mount_mfs -i 256 -s 592 -P /var/run/dev swap /dev http://marc.info/?l=openbsd-miscm=120086358424135w=2 explains why this doesn't work the same way in 4.2 and suggests an alternative. ___ Soekris-tech mailing list Soekris-tech@lists.soekris.com http://lists.soekris.com/mailman/listinfo/soekris-tech
Re: [Soekris] Smallest possible MFS /dev on OpenBSD
On Tue, 2008-01-15 at 14:56 +0200, Lars Noodén wrote: I've got OpenBSD 4.2 on a net4801 and am mounting /dev in RAM. I'd like to reduce the amount of memory used even further. Currently only %4 is used: Filesystem SizeUsed Avail Capacity Mounted on mfs:21800 853K 34.0K777K 4%/dev What should I be aware of in /etc/fstab to minimize the memory footprint of /dev? Currently, I have: swap /dev mfs rw,-P/dev.base,-i1,-s2300,-c264,-m5,nosuid 0 0 Couldn't resist .. here's ho far I got after about 45 mins. of testing: # mount_mfs -s 512 -b 32768 -f 32768 -P/var/dev -o nosuid swap /mnt/test/ # df /mnt/test Filesystem 512-blocks Used Avail Capacity Mounted on mfs:17962 192 1286467%/mnt/test/ # df -h /mnt/test Filesystem SizeUsed Avail Capacity Mounted on mfs:17962 96.0K 64.0K 32.0K67%/mnt/test/ Note: '-i' option is ignored here - it doesn't make any noticeable difference at all. Block and fragment size seem to be the issues here. With these set to the defaults, I never got past 13%. You would only need to change the default bpi if you run out of inodes. Maintaining fragments appears to be pretty disk-intensive, I suspect that if (blk_siz == frag_siz (or whatever)) then it's turned off altogether. I couldn't reproduce Jean-Yves' 23.0K (mount_mfs -i 256 -s 592 -P /var/run/dev swap /dev): # mount_mfs -i 256 -s 512 -P/var/dev -o nosuid swap /mnt/test # df -h /mnt/test mfs:29060 143K 15.0K121K11%/mnt/test I suspect that the '-s' value 592 was a typo, since it was rejected over here: mount_mfs: reduced number of fragments per cylinder group from 72 to 64 to enlarge last cylinder group mount_mfs: inode table does not fit in cylinder group I can't find any hard data - apart from claims and statements - about dynamic growth (nor shrinkage!) of the MFS partition, but should any process hijack /dev e.g. as it's temp dir, then 96K (or 23, if possible), should be a significant improvement over the 853K in Lars' original posting, even if it's only a max. value. Bill -- What's a computer? - MES ___ Soekris-tech mailing list Soekris-tech@lists.soekris.com http://lists.soekris.com/mailman/listinfo/soekris-tech
Re: [Soekris] Smallest possible MFS /dev on OpenBSD
I've got OpenBSD 4.2 on a net4801 and am mounting /dev in RAM. I'd like to reduce the amount of memory used even further. Currently only %4 is used: Filesystem SizeUsed Avail Capacity Mounted on mfs:21800 853K 34.0K777K 4%/dev What should I be aware of in /etc/fstab to minimize the memory footprint of /dev? Currently, I have: swap /dev mfs rw,-P/dev.base,-i1,-s2300,-c264,-m5,nosuid 0 0 I think that ramfs is dynamic, ie physical memory is not reserved during mount_mfs execution. To reduce the /dev memory fs space : - you can reduce the inodes density with -i. Default is one inode for 8196 bytes. - delete unused devices. Here is the command I use on my Soekris targets : # mount_mfs -i 256 -s 592 -P /var/run/dev swap /dev And the result is : # df -h /dev Filesystem SizeUsed Avail Capacity Mounted on mfs:31196 23.0K6.0K 16.0K27%/dev Number of files in /dev: # ls /dev | wc -l 307 Random changes to mfs' parameters aren't getting me anywhere. There should be a rational way of arriving at optimal settings for mfs: -b block-size -c fragments-per-cylinder-group -f frag-size -i bytes -m free-space -s size ___ Soekris-tech mailing list Soekris-tech@lists.soekris.com http://lists.soekris.com/mailman/listinfo/soekris-tech
Re: [Soekris] Smallest possible MFS /dev on OpenBSD
Jean-Yves Boisiaud wrote: ... To reduce the /dev memory fs space ... - delete unused devices. What is the safest or most efficient method to go about doing that? Would the output from dmassage -t be useful there? Regards, -Lars ___ Soekris-tech mailing list Soekris-tech@lists.soekris.com http://lists.soekris.com/mailman/listinfo/soekris-tech
Re: [Soekris] Smallest possible MFS /dev on OpenBSD
On 2008/01/16 17:43, Lars Noodén wrote: Jean-Yves Boisiaud wrote: ... To reduce the /dev memory fs space ... - delete unused devices. # du -h /dev 1.0K/dev/fd 34.0K /dev What is the safest or most efficient method to go about doing that? The safest and most efficient method is to leave it alone. If you have a real problem with RAM use, there's probably some easier and safer way to fix it than shaving off kilobytes here. But if you're not at that point, why worry? :-) ___ Soekris-tech mailing list Soekris-tech@lists.soekris.com http://lists.soekris.com/mailman/listinfo/soekris-tech
Re: [Soekris] Smallest possible MFS /dev on OpenBSD
Lars Noodén a écrit : I've got OpenBSD 4.2 on a net4801 and am mounting /dev in RAM. I'd like to reduce the amount of memory used even further. Currently only %4 is used: Filesystem SizeUsed Avail Capacity Mounted on mfs:21800 853K 34.0K777K 4%/dev What should I be aware of in /etc/fstab to minimize the memory footprint of /dev? Currently, I have: swap /dev mfs rw,-P/dev.base,-i1,-s2300,-c264,-m5,nosuid 0 0 Random changes to mfs' parameters aren't getting me anywhere. There should be a rational way of arriving at optimal settings for mfs: -b block-size -c fragments-per-cylinder-group -f frag-size -i bytes -m free-space -s size Regards, -Lars I have been trying -s1024 but it wont mount I think this is the smallest footprint you can have. But if you find smaller I'm interrested. Regards smime.p7s Description: S/MIME Cryptographic Signature ___ Soekris-tech mailing list Soekris-tech@lists.soekris.com http://lists.soekris.com/mailman/listinfo/soekris-tech
