files damaged on memory disk on Marvell Discovery 78100

[Rafal Jaworowski]

On 2010-05-19, at 08:19, Matthias Reyelt wrote:

> I have observed a strange behaviour on the Marvell Discovery:
> 
> I have a memory disk for /etc and /opt:
> /dev/md0 on /etc (ufs, local)
> /dev/md1 on /opt (ufs, local)
> 
> When I copy files to that disk, which are larger than 0x1ffff (131071 bytes), 
> these files differ from the original. This occurs only when copying to md. 
> 
> Kernel is:
> FreeBSD discovery1 8.0-STABLE FreeBSD 8.0-STABLE #0 r206836: Mon Apr 19 
> 12:53:42 CEST 2010    
> root at vbcspc12.bcs.brunel.local:/usr/obj/arm/root/ARM/8/sys/DB-78XXX  arm
> 
> I had a look into the damaged file and found some excerpts from files located 
> in /etc (which is also in RAM):
> ------------------------------------------------------------
> passwd: compat
> passwd_compat: nis
> shells: files
> -----------------------------------------------------------------
> ...
> -----------------------------------------------------------------
> staff:*:20:
> sshd:*:22:
> smmsp:*:25:
> mailnull:*:26:
> guest:*:3-���
> ------------------------------------------------------------------
> 
> Looks as if the CPU has problems accessing the RAM. I have already changed the 
> RAM, so I don't think it's a hardware problem. 
> 
> Any idea?


Try turning off clustering on the filesystem(s). There was least one known problem in this area leading to cache incoherency, see this thread for more details (and how-to): http://lists.freebsd.org/pipermail/freebsd-arm/2008-December/001423.html

Rafal