John, If what your really after is significantly higher performance and io throughput, consider 10K speed drives. The increased speed doesn't directly translate into increased noise.
Look at the write, seeks, and latency times below. 10K speed drives
with 16M buffers sit right in the middle of performance and price (lower
is better on both points).
$169.99 Western Digital VelociRaptor WD1500HLFS
150GB 10000 RPM SATA 3.0Gb/s Hard Drive (bare drive) - OEM
* Cache: 16MB
* Form Factor: 3.5"
* Average Seek Time: 4.2ms
* Average Write Time: 4.7ms
* Average Latency: 5.5ms
* Features: The 2.5" WD Veloci Raptor is enclosed in a 3.5"
enterprise-class mounting frame.
* Parts: 5 years limited
* Labor: 5 years limited
* Model #: WD1500HLFS
* Item #: N82E16822136296
*
Versus a 7200 Speed 16M
$54.99 Seagate Barracuda 7200.10 ST3250410AS 250GB 7200 RPM SATA 3.0Gb/s
Hard Drive - OEM
* Cache: 16MB
* Form Factor: 3.5"
* Average Seek Time: 8.5ms
* Average Write Time: 10ms
* Average Latency: 4.16ms
* Model #: ST3250410AS
* Item #: N82E16822148262
$74.99 Seagate Barracuda ES.2 ST3250310NS 250GB 7200 RPM SATA 3.0Gb/s
Hard Drive - OEM
* Cache: 32MB
* Form Factor: 3.5"
* Average Seek Time: 8.5ms
* Average Write Time: 9.5ms
* Average Latency: 4.16ms
* Model #: ST3250310NS
* Item #: N82E16822148309
$189 Fujitsu MBA3147NC 147GB 15000 RPM SCSI Ultra320 80pin Hard Drive -
OEM
* Cache: 8MB (16MB is $249.99, with no increase in metrics)
* Form Factor: 3.5"
* Average Seek Time: 3.4ms
* Average Write Time: 3.9ms
* Average Latency: 2ms
* Model #: MBA3147NC
* Item #: N82E16822116061
Although hearing you say raid5, and reduced opportunity for data loss, I
would say Large 16K/7200 SataII drives could be your best choice. (lots
of them, as in 4+ drives (((NOT 3))))
For more detailed info on the data transfer issue, look into the kernel
docs for FileSystem Driver, or EXT3 Drivers.
Here is a hdparam article that sheds some like on tuning opportunities -
the real story:
http://www.linuxdevcenter.com/pub/a/linux/2000/06/29/hdparm.html
James,
On Wed, 2008-12-10 at 09:43 -0500, John McKelvey wrote:
> Folks,
>
> I want to add 3 identical hard drives under Raid 5. Am considering
> Seagate SATA II server drives. One question is does it really make
> much difference to use drives with 16Mbytes cache rather than 32Mbytes
> cache?
>
> Thanks!
>
> John McKelvey
> _______________________________________________
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> [email protected]
> http://fortwaynelug.org/mailman/listinfo/fwlug_fortwaynelug.org
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