Read-only disk problem

[Engineering]

Hi, I've attached some more info. Doing a fsdump shows the following changes
over reboot

magic	19540119 (UFS2)	time	Tue Aug 30 03:08:04 2011
...
cg 1:
magic	90255	tell	4b1c000	time	Tue Aug 30 03:08:04 2011

Changes to

magic	19540119 (UFS2)	time	Tue Aug 30 03:13:14 2011
...
cg 1:
magic	90255	tell	4b1c000	time	Tue Aug 30 03:13:14 2011

Sam

-----Original Message-----
From: owner-freebsd-fs at freebsd.org [mailto:owner-freebsd-fs at freebsd.org] On
Behalf Of Engineering
Sent: Monday, August 29, 2011 2:15 PM
To: freebsd-fs at freebsd.org
Subject: Read-only disk problem

Please let me know if this is the wrong place to ask. I am working on an
embedded system using FreeBSD 7.2, bootinf and running off of flash memory.
In order to not burn out the flash, I use the 'diskless' scripts and mount
the flash read-only. I have used this configuration successfully in the
past.

I've recently added a utility to check for disk corruption, basically
checksumming the / and /usr partitions. Since they are both read-only, I
thought this would work. What I have discovered is that something in the
partition is changing between boots.

I dd'd the flash over a couple of boots, and compared the binaries to see
what was changing. It is a small amount of data, spread across the disk, in
an interval that looks very similar to the interval of the 'superblocks'

Is there any data that is written to the disk at boot or mount time, and if
so, is there a way to prevent it?

Thanks
Sam

_______________________________________________
freebsd-fs at freebsd.org mailing list
http://lists.freebsd.org/mailman/listinfo/freebsd-fs
To unsubscribe, send any mail to "freebsd-fs-unsubscribe at freebsd.org"