Re: Samsung 32GB SATA SSD tested

From: behrangs <behrang(dot)sa(at)gmail(dot)com>
To: pgsql-performance(at)postgresql(dot)org
Subject: Re: Samsung 32GB SATA SSD tested
Date: 2008-09-03 04:20:04
Message-ID: 19282698.post@talk.nabble.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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