On Mon, 11 Jan 2010, bank kus wrote:
However I noticed something weird, long after the file operations
are done the free memory doesnt seem to grow back (below)
Essentially ZFS File Data claims to use 76% of memory long after the
file has been written. How does one reclaim it back. Is ZFS File
Data a pool that once grown to a size doesnt shrink back even though
its current contents might not be used by any process?
It is normal for the ZFS ARC to retain data as long as there is not
other memory pressure. This should not cause a problem other than a
small delay when starting an application which does need a lot of
memory since the ARC will give memory back to the kernel.
For better interactive use, you can place a cap on the maximum ARC
size via an entry in /etc/system:
http://www.solarisinternals.com/wiki/index.php/ZFS_Evil_Tuning_Guide#ARCSIZE
For example, you could set it to half your (8GB) memory so that 4GB is
immediately available for other uses.
* Set maximum ZFS ARC size to 4GB
* http://www.solarisinternals.com/wiki/index.php/ZFS_Evil_Tuning_Guide#ARCSIZE
* set zfs:zfs_arc_max = 0x100000000
Bob
--
Bob Friesenhahn
bfrie...@simple.dallas.tx.us, http://www.simplesystems.org/users/bfriesen/
GraphicsMagick Maintainer, http://www.GraphicsMagick.org/
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