Re: Has anyone else seen any form of in memory or on disk corruption?

gnn_at_freebsd.org wrote:

> Hi,
> 
> I've been working on the following brain teasing (breaking?) problem
> for about a week now.  What I'm seeing is that on large memory
> machines, those with more than 4G of RAM, the ungzipping/untarring of
> files fails due to gzip thinking the file is corrupt.  The way to
> reproduce this is:
> 
> 1) Create a bunch of gzip/tar balls in the 1-20MB range.
> 2) Reboot FreeBSD 7.0 release
> 3) Run gzip -t over all the files.
> 
> I have hundreds of these files to run this over, and a full check
> takes about 3 hours, but I usually see some form of corruption within
> the first 20 minutes.
> 
> Other important factors:
> 
> 1) This is on very modern, 2P/4Core (8 cores total) hardware
> 2) The disks are 1TB SATA set up in JBOD.
> 3) The machines have 16G of RAM.
> 4) Corruption is seen only after a reboot, if the machines continue to
> run corruption is never seen again, until another reboot.
> 5) The systems are all Xeon running amd64
> 6) The disk controller is an AMCC 9650, but we do see this very rarely
> with the on board controlller.
> 7) All boards are
> 
> http://www.supermicro.com/products/motherboard/Xeon1333/5400/X7DWU.cfm
> 
> 8) All machines have 3 1TB drives.
> 9) The corruption is in 4K chunks.  That is N x 4K.
> 10) Files are not normally corrupted on disk, but this can happen.
> 
> I have already tried a few of the obvious things, such as making sure
> that we sync pages before we shutdown the twa driver.
> 
> Given what I have seen I believe this is something that happens from
> startup, and not at shutdown.
> 
> Thoughts?

Have you tried turning off background fsck on boot to see if the problem
goes away?


-- 
Mark Atkinson
atkin901_at_yahoo.com
(!wired)?(coffee++):(wired);