Date: Mon, 10 Jan 2005 18:08:40 +0800 (CST) From: Barath S <barath_yes@yahoo.com.sg> To: Scott Long <scottl@freebsd.org> Cc: FreeBsd-MailGrp <freebsd-fs@freebsd.org> Subject: Re: using mfs of size > 64Mb and system stability Message-ID: <20050110100840.29845.qmail@web30301.mail.mud.yahoo.com> In-Reply-To: <41E01905.3040200@freebsd.org>
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Initially, I didn't go for swap based fs as I felt that the memory occupied will be from the swap area. As you are saying that the allocation will be from buffer/cache, I will test swap-mfs. Updates on malloc-mfs: System didn't crash when creating malloc based fs with "-o reserve" option for a size of 128Mb. But, when tried creating two mfs(s) each with sizes of 24Mb and 1Mb, the system rebooted itself. I tried this in a system with 1G memory. Another observation is that even with this system w/o "-o reserve", the system hangs immediately with mfs-size > 64Mb. Thanks and regards --- Scott Long <scottl@freebsd.org> wrote: > Using the swap option really is the preferred > method. The available > kernel malloc pool is limited and is scaled on the > amount of system > RAM that you have; on my 256MB laptop, it's > reporting only 85MB > available for kernel malloc. So this would explain > why trying to > malloc 128MB for md could fail =-). > > With the swap option, pages are allocated from the > buffer/cache and > held there. They are only swapped to disk when the > system is under > memory pressure, otherwise they stay in RAM. > > Scott > > Barath S wrote: > > Thank you Arne. > > I didn't try with 'swap' option as my requirement > is > > to have the files in memory. I will test with 5.3 > and > > see it that works. > > regards > > --- Arne Wörner <arne_woerner@yahoo.com> wrote: > > > >>--- Barath S <barath_yes@yahoo.com.sg> wrote: > >> > >>>My intention is create a file system in memory of > >> > >>size > >> > >>>>128Mb and use that for my application. But, I > >>> > >>>couldn't do that as my system hangs whenever I > >> > >>create > >> > >>>a mfs of size > 64Mb. I did the following... > >>> > >>>a) Configured memory file system of size 128Mb > >> > >>using > >> > >>>'mdmfs' command with 'malloc' option. When I > tried > >> > >>to > >> > >>>copy files to this mfs, m/c hanged after copying > >> > >>some > >> > >>>files. > >>>b) Then I rebooted by m/c and configured memory > >> > >>file > >> > >>>system of size 64Mb and this time the copying > >>>operation was successful > >>>c) I observed that the system hanged whenever I > >>>configure a mfs of size > 64Mb and used that mfs > >>> > >>>a) Can someone provide me hints on what could be > >> > >>the > >> > >>>problem ? > >>> > >> > >>I use R5.3. According to the man page mdconfig(8) > a > >>md of type > >>malloc should use "-o reserve", if it is large and > >>to be "filled" > >>(I think the man page means "filled quickly"): > >> "If the -o reserve option is not set, creating > and > >>filling > >> a large malloc-backed memory disk is a very > easy > >>way to > >> panic a system." > >> > >>Maybe that helps? > >> > >>Did you try type "swap"? > >> > >>-Arne > >> > >> > >> > >> > >>__________________________________ > >>Do you Yahoo!? > >>The all-new My Yahoo! - Get yours free! > >>http://my.yahoo.com > >> > >> > >> > > > > > > __________________________________________________ > > Do You Yahoo!? > > Download the latest ringtones, games, and more! > > http://sg.mobile.yahoo.com > > _______________________________________________ > > freebsd-fs@freebsd.org mailing list > > > http://lists.freebsd.org/mailman/listinfo/freebsd-fs > > To unsubscribe, send any mail to > "freebsd-fs-unsubscribe@freebsd.org" > > __________________________________________________ Do You Yahoo!? Download the latest ringtones, games, and more! http://sg.mobile.yahoo.com
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