Message-ID: <19282698.post@talk.nabble.com>
Date: Tue, 2 Sep 2008 21:20:04 -0700 (PDT)
From: behrangs <behrang.sa@gmail.com>
To: pgsql-performance@postgresql.org
Subject: Re: Samsung 32GB SATA SSD tested
In-Reply-To: <1216771475.23796.14.camel@squeak.gghcwest.com>
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Jeff,

Some off topic questions:

Is it possible to boot the OS from the ioDrive? If so, is the difference in
boot up time noticeable?

Also, how does ioDrive impact compilation time for a moderately large code
base? What about application startup times?

Cheers,
Behrang


Jeffrey Baker wrote:
> 
> For background, please read the thread "Fusion-io ioDrive", archived at
> 
> http://archives.postgresql.org/pgsql-performance/2008-07/msg00010.php
> 
> To recap, I tested an ioDrive versus a 6-disk RAID with pgbench on an
> ordinary PC.  I now also have a 32GB Samsung SATA SSD, and I have tested
> it in the same machine with the same software and configuration.  I
> tested it connected to the NVIDIA CK804 SATA controller on the
> motherboard, and as a pass-through disk on the Areca RAID controller,
> with write-back caching enabled.
> 
>                            Service Time Percentile, millis
>        R/W TPS   R-O TPS      50th   80th   90th   95th
> RAID      182       673         18     32     42     64
> Fusion    971      4792          8      9     10     11
> SSD+NV    442      4399         12     18     36     43
> SSD+Areca 252      5937         12     15     17     21
> 
> As you can see, there are tradeoffs.  The motherboard's ports are
> substantially faster on the TPC-B type of workload.  This little, cheap
> SSD achieves almost half the performance of the ioDrive (i.e. similar
> performance to a 50-disk SAS array.)  The RAID controller does a better
> job on the read-only workload, surpassing the ioDrive by 20%.
> 
> Strangely the RAID controller behaves badly on the TPC-B workload.  It
> is faster than disk, but not by a lot, and it's much slower than the
> other flash configurations.  The read/write benchmark did not vary when
> changing the number of clients between 1 and 8.  I suspect this is some
> kind of problem with Areca's kernel driver or firmware.
> 
> On the bright side, the Samsung+Areca configuration offers excellent
> service time distribution, comparable to that achieved by the ioDrive.
> Using the motherboard's SATA ports gave service times comparable to the
> disk RAID.
> 
> The performance is respectable for a $400 device.  You get about half
> the tps and half the capacity of the ioDrive, but for one fifth the
> price and in the much more convenient SATA form factor.
> 
> Your faithful investigator,
> jwb
> 
> 
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