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cc: freebsd-current@FreeBSD.org
cc: bde@zeta.org.au
Subject: Re: panic in ffs (Re: hangs in nbufkv)
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Matthew Dillon wrote:

>    Well, it's possible that UFS has bugs related to large block sizes.
>    People have gotten bitten on and off over the years but usually it 
>    works ok if you leave the 8:1 blocksize:fragsize ratio intact.  e.g.
>    if you have a 64KB block size then you should use a 8K frag size.
>    If you have a 32KB block size then you should use a 4K frag size.
>  
>
This is the case here: fs_bsize 65536, fs_fsize 8192.

>    I think the buffer cache itself is is likely not the source of this
>    particular bug.
>  
>
I don't know, how, but the bug seems triggered by upping the 
net.inet.udp.maxdgram from 9216 (default) to 16384 (to match the NFS 
client's wsize). Once I do that, the machine will either panic or just 
hang a few minutes into the heavy NFS writing (Sybase  database dumps 
from a Solaris server). Happened twice already...

    -mi

P.S. Thanks for prompt responses and advice, BTW!