Re: Solaris ZFS on Linux [Was: Re: the " 'official' point of view" expressed by kernelnewbies.org regarding reiser4 inclusion]

[Matthias Andree]

Adrian Ulrich schrieb am 2006-08-01:

> > suspect, particularly with 7200/min (s)ATA crap. 
> 
> Quoting myself (again):
> >> A quick'n'dirty ZFS-vs-UFS-vs-Reiser3-vs-Reiser4-vs-Ext3 'benchmark'
> 
> Yeah, the test ran on a single SATA-Harddisk (quick'n'dirty).
> I'm so sorry but i don't have access to a $$$ Raid-System at home. 

I'm not asking for you to perform testing on a $$$$ RAID system with
SCSI or SAS, but I consider the obtained data (I am focussing on
transactions per unit of time) highly suspicious, and suspect write
caches might have contributed their share - I haven't seen a drive that
shipped with write cache disabled in the past years.

> > sdparm --clear=WCE /dev/sda   # please.
> 
> How about using /dev/emcpower* for the next benchmark?

No, it is valid to run the test on commodity hardware, but if you (or
the benchmark rather) is claiming "transactions", I tend to think
"ACID", and I highly doubt any 200 GB SATA drive manages 3000
synchronous writes per second without causing either serious
fragmentation or background block moving.

This is a figure I'd expect for synchronous random access to RAM disks
that have no seek and rotational latencies (and research for hybrid
disks w/ flash or other nonvolatile fast random access media to cache
actual rotating magnetic plattern access is going on elsewhere).

I didn't mean to say your particular drive were crap, but 200GB SATA
drives are low end, like it or not -- still, I have one in my home
computer because these Samsung SP2004C are so nicely quiet.

> I mighty be able to re-run it in a few weeks if people are interested
> and if i receive constructive suggestions (= Postmark parameters,
> mkfs options, etc..)

I don't know Postmark, I did suggest to turn the write cache off. If
your systems uses hdparm -W0 /dev/sda instead, go ahead. But you're
right to collect and evaluate suggestions first if you don't want to run
a new benchmark every day :)

-- 
Matthias Andree
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