Re: /tmp on mfs
2009/10/20 Christopher Hilton : > Reading the list yesterday I came across a little controversy about swap > backed /tmp filesystems. I've been using this in my /etc/rc.conf > > tmpmfs="YES" # Set to YES to always create an mfs /tmp, NO to > never > tmpsize="1g" # Size of mfs /tmp if created > tmpmfs_flags="-S -o async,noexec" # Extra mdmfs options for the mfs > /tmp Not to butt in (and tangentially, anyway), but noexec on /tmp will cause "make installworld" to fail. Or at least, it did last time I tried it (2005?). If you never build world, I guess this is completely unimportant. -- -- ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to "freebsd-questions-unsubscr...@freebsd.org"
Re: /tmp on mfs
On Tue, 20 Oct 2009 11:20:38 -0400, Christopher Hilton wrote: > Reading the list yesterday I came across a little controversy about swap > backed /tmp filesystems. I've been using this in my /etc/rc.conf > > tmpmfs="YES"# Set to YES to always create an mfs /tmp, NO to never > tmpsize="1g"# Size of mfs /tmp if created > tmpmfs_flags="-S -o async,noexec" # Extra mdmfs options for the mfs /tmp > > To mount /tmp on a swap backed filesystem. I've been assuming that > data stored in the /tmp directory was held in RAM and then written to > the swap space only when the system had a more pressing need for the > RAM. I typically configure my systems with swap == 2 * RAM or more. > And on the systems in question I have at least 1Gb of RAM. I was > hoping to use this trick to enhance the performance of the postgresql > database (temp_tablespace=/tmp/pgsql/) Is my assumption about > where the data in a temporary file is stored incorrect? Hi Christopher, The rc.conf(5) options for `tmpmfs' and `varmfs' use the mdmfs(8) to create the respective filesystems. The default behavior of mdmfs(8) is to create a swap-backed filesystem. Swap-backed filesystems, as the manpage of mdconfig(8) described them, work exactly as you wrote: swap Storage for this type of memory disk is allocated from buffer memory. Pages get pushed out to the swap when the system is under memory pressure, otherwise they stay in the operating memory. Using swap backing is generally preferable over malloc backing. So your understanding of the way tmpmfs behaves is fine. ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to "freebsd-questions-unsubscr...@freebsd.org"
Re: /tmp on mfs
Christopher Hilton wrote: > Reading the list yesterday I came across a little controversy about > swap backed /tmp filesystems. I've been using this in my /etc/rc.conf > > tmpmfs="YES"# Set to YES to always create an mfs /tmp, NO > to never > tmpsize="1g"# Size of mfs /tmp if created > tmpmfs_flags="-S -o async,noexec" # Extra mdmfs options for the > mfs /tmp > > To mount /tmp on a swap backed filesystem. I've been assuming that > data stored in the /tmp directory was held in RAM and then written to > the swap space only when the system had a more pressing need for the > RAM. I typically configure my systems with swap == 2 * RAM or more. > And on the systems in question I have at least 1Gb of RAM. I was > hoping to use this trick to enhance the performance of the postgresql > database (temp_tablespace=/tmp/pgsql/) Is my assumption about > where the data in a temporary file is stored incorrect? > Thats certainly always been my interpretation of the manpage. "Storage for this type of memory disk is allocated from buffer memory. Pages get pushed out to the swap when the system is under memory pressure, otherwise they stay in the operating memory." If thats not the case I'd be interested to know how it does work. Vince > -- Chris > ___ > freebsd-questions@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-questions > To unsubscribe, send any mail to > "freebsd-questions-unsubscr...@freebsd.org" ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to "freebsd-questions-unsubscr...@freebsd.org"
/tmp on mfs
Reading the list yesterday I came across a little controversy about swap backed /tmp filesystems. I've been using this in my /etc/rc.conf tmpmfs="YES"# Set to YES to always create an mfs /tmp, NO to never tmpsize="1g"# Size of mfs /tmp if created tmpmfs_flags="-S -o async,noexec" # Extra mdmfs options for the mfs /tmp To mount /tmp on a swap backed filesystem. I've been assuming that data stored in the /tmp directory was held in RAM and then written to the swap space only when the system had a more pressing need for the RAM. I typically configure my systems with swap == 2 * RAM or more. And on the systems in question I have at least 1Gb of RAM. I was hoping to use this trick to enhance the performance of the postgresql database (temp_tablespace=/tmp/pgsql/) Is my assumption about where the data in a temporary file is stored incorrect? -- Chris ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to "freebsd-questions-unsubscr...@freebsd.org"
