On Thu, 10 Oct 2002, Oliver Fromme wrote:
> Wolfieee <[EMAIL PROTECTED]> wrote:
>  > what about vnconfiging some files on the netapp thing, this way the 
>  > *bsd can see the vnconfig files as local raw disk partitions?
> 
> That wouldn't make a difference, because the NetApp Filer would still
> schedule mtime updates for evey write access to the file that has been
> vnconfiged on the client.

Probably talking through my hat, here, but doesn't NetApp use a LFS
(log-structured file system) variant?  It's been a couple years since we
got ours, but at the time I reviewed it for use as a central database
filesystem.  I'm pretty sure it used an LFS, partially because of the
sweet RAID-write semantics - basically, you never have to
read-modify-write to deal with the parity update, you simply generate an
entire chunk worth of data in NVRAM, and write it all at once, with
parity.

In any case, assuming that I got the analysis right, that means the mtime
update should be essentially free, since it's already going to be writing 
a new inode for the file to capture any new blocks written.

http://www.netapp.com/tech_library/3001.html#I4, also note the Ousterhout
reference in the bibliography.  An even stronger indicator is at
http://www.netapp.com/tech_library/3002.html#I35.

Later,
scott


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