On Mon, 7 Dec 2009, Richard Bruce wrote:
I started copying over all the data from my existing workstation.
When copying files (mostly multi-gigabyte DV video files), network
throughput drops to zero for ~1/2 second every 8-15 seconds. This
throughput drop corresponds to drive activity on the Opensolaris
box. The ZFS pool drives show no activity except every 8-15
seconds. As best as I can guess, the Opensolaris box is caching
traffic and batching it to disk every so often. I guess I didn't
expect disk writes to interrupt network traffic. Is this correct?
This is expected behavior. From what has been posted here, these are
the current buffering rules:
up to 7/8ths of available memory
up to 5 seconds worth of 100% write I/O time
up to 30 seconds without a write
and if you don't like it, you can use the zfs:zfs_arc_max tunable in
/etc/system to set a maximum amount of memory to be used prior to a
write. This may be useful on systems with a large amount of memory
and which want to limit the maximum delay time due to committing the
zfs transation group. There will still be interruptions, but the
interruptions can be made briefer (and more often).
Bob
--
Bob Friesenhahn
bfrie...@simple.dallas.tx.us, http://www.simplesystems.org/users/bfriesen/
GraphicsMagick Maintainer, http://www.GraphicsMagick.org/
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