A couple of weeks ago I wrote:
> I have began upgrading my servers to 4.1.2 mainly to take advantage of the new
> `fast fsck`.
> I have not yet seen any literature on the subjct-
> 1) How is it implemented ?
> 2) will it work on filesystems that were newfs-ed on SunOs 4.0.3/4.1 ?
> 3) Is there a way to determine under which OS the file system was newfs-ed ?
Have received a number of answers - fullest from glenn@fourx.Aus.Sun.COM:
There is a "clean" flag in the superblock. Every time sync() runs it
marks the filesystem as clean. When fsck checks the disk it reads this
flag and if it is "clean" then it skips the rest of the disk checks. The
algorithm has also been improved to check multiple disks in parallel
somewhat better than earlier versions. There is some info hidden away
in the fsck(8) and fs(5) man pages.
I don't know for sure, it's been a while since I used a 4.0.3 system
:-), I think it will be ok on 4.1 but you will need to convert 4.0.3
from static to dynamic table format. See fsck(8) for details on
converting, particularly the -c option. If in doubt just run fsck -c,
it will prompt you for the conversion, eg:
# fsck -c -n /dev/rsd3g
** /dev/rsd3g (NO WRITE)
CONVERT TO OLD FILE SYSTEM FORMAT? no
This is on a 4.1.2 system. On an old format it will ask if you wish to
convert to the new format.
3) Use the dumpfs(8) command to look at the file system info. The first line of
out put looks like this:
$ dumpfs /dev/rsd3g | more
magic 11954 format dynamic time Tue Jul 21 15:23:34 1992
The format can be either dynamic (4.1.X) or the older static. To
convert from one to the other use fsck -c.
Or use the fsck -c command shown above.
Thanks also to:
Casper H.S. Dik" <firstname.lastname@example.org>
Matt Crawford <email@example.com>
Ken Nawyn <firstname.lastname@example.org>
Robert Haddick <email@example.com>
ogicse!bit!jayl@sun.Eng.Sun.COM (Jay Lessert)
Chris Keane <firstname.lastname@example.org.COM.AU>
David Fetrow <email@example.com>
Dwight Ernest <firstname.lastname@example.org>
email@example.com (Matthew Donaldson)
firstname.lastname@example.org (John D Schneider)
email@example.com (Frank P. Bresz)
kalli!glenn@fourx.Aus.Sun.COM (Glenn Satchell)
-- ========================================================================== || Eli Lopez, Systems Manager, National Semiconductor, Israel || \\ Phone: 972-52-594-236, Fax: 972-52-558-322 // ====================================================================
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