zfs discuss - Oct 2009 - Performance of ZFS and UFS inside local/global zone

Dear all,

I was interested in the performance difference between filesystem operations
inside a local and global zone. Therefore I utilized filebench and made several
performance tests with the OLTP script for filebench. Here are some of my
results:

-> In the global zone (filebench operates on basis of UFS): [b]281,850.2
IOPS/sec[/b]
-> In the local zone (filebench operates on basis of UFS): [b]181,716
IOPS/sec[/b]
So a huge difference bewteen the local and global zone when operating on basis
of UFS.

After I saw the huge difference I wondered if I will see such a huge difference
when using ZFS. Here are the results:
-> In the global zone (filebench operates on basis of ZFS): [b]1,710,268.1
IOPS/sec[/b]
-> In the local zone (filebench operates on basis of ZFS): [b]449,332.6
IOPS/sec[/b]
I was a little bit surprised to see a big difference again. Besides: ZFS
outperforms UFS - but this is already known.

So in a first analysis I suspected the loop-back-device driver to cause the
performance degredation. I repeated the tests without the loop-back-driver by
mounting UFS device directly inside the zone. I couldn''t discover the
performance degredation again.

This leads me to the assumption, that the loop-back-driver causes the
performance degredation - but how can I make sure it is the loop-back-driver and
not anything else? Does anyone has an idea how to explore this phenomen?

Regards
Andr?
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Very easy:

	- make a directory
	- mount it using lofs

run filebench on both directories.

It seems like that we need to make lofs faster.

Casper

Hi Casper,

I did that.

1. I created a directory and mounted the device in the global zone -> run 
filebench
<umount device>
2. I created a directory and mounted the device in the local zone -> run 
filebench
--> No difference

It seems the loop-back-driver causes the performance degredation - but how 
can I prove this thesis?

andr?



Von:
Casper.Dik at Sun.COM
An:
Andre Boegelsack <boegelsa at in.tum.de>
Kopie:
zfs-discuss at opensolaris.org
Datum:
20.10.2009 15:23
Betreff:
Re: [zfs-discuss] Performance of ZFS and UFS inside local/global zone
Gesendet von:
casper at holland.sun.com





Very easy:

                 - make a directory
                 - mount it using lofs

run filebench on both directories.

It seems like that we need to make lofs faster.

Casper


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>I did that.
Isn''t that sufficient proof?

Perhaps run both tests in the global zone?

Casper

So is there is a Change Request on this?
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