Date: Wed, 6 Oct 2004 16:01:26 +0200 (CEST) From: "Julian Stacey" <jhs@berklix.org> To: freebsd-hackers@freebsd.org Cc: jhs@berklix.com Subject: fsck: How to reduce memory usage - to avoid out of swap on boot ? Message-ID: <200410061401.i96E1QfJ003850@laps.jhs.private>
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On 4.10-RELEASE with real memory = 10485760 (10240K bytes) & big disc partition: disklabel ad0s1 sectors/unit: 160071597 # size offset fstype [fsize bsize bps/cpg] h: 156613309 3458288 4.2BSD 2048 16384 89 # (Cyl. 215*- 9963*) On a dirty reboot, fsck hangs single user saying: out of swap space. This on an embedded headless host, delivered to remote sites. Plugging in a monitor card is problematic, so it needs to come up multi user & net reachable. Options: - Split the partition in several. - Ugly, Maybe I could remerge them with ccd or vinum?] not tried those before, but still an ugly solution. - More memory: Mainboard has 2M & just 1 slot, currently with an 8M RAM, but I'm looking for a 16M slice & will see if mboard accepts it & if fsck considers that enough. ( After forcing it multiuser I saw: # UID PID PPID CPU PRI NI VSZ RSS WCHAN STAT TT TIME COMMAND # 0 455 419 113 42 0 7064 1820 - R+ p1 2:42.52 fsck -y /usr1& for comparison on another 4.10-RELEASE box with an 18G drive it grew to # 0 625 553 0 -6 0 7580 7448 physst DL+ p0 0:12.50 fsck -y /usr3 (Could man fsck document roughly how much ram needed for what size disc ? ) - Add ,noato to /etc/fstab & manually fsck & mount /usr1 from rc.local (I imagine swapinfo by then reports more swap available) - ugly. & I think Ive tried that before somewhere else recently, (on 5-current admittedly) I recall no clean bit caused a hang, even thouth ,noauto - /usr/src/sbin/fsck/fsck.h, maybe I could eg halve one or both of these: #define MAXBUFSPACE 40*1024 /* maximum space to allocate to buffers */ #define INOBUFSIZE 56*1024 /* size of buffer to read inodes in pass1 */ I quickly paged through all of /usr/src/sbin/fsck/ but didnt see much else likely. Any suggestion what to hack ? Must be some define type `take so much RAM' lines in there :-) PS I think it's pass1 that's running out of swap, but maybe pass2, I can't check till backup complete. Ideas ? - Julian Stacey. Unix,C,Net & Sys. Eng. Consultant, Munich. http://berklix.com Mail Ascii; Html deleted as Spam. Ihr Rauch = mein allergischer Kopfschmerz.
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