rwessel (robertwessel@yahoo.com) on 8/19/08 wrote:
---------------------------

>While SSD is still pretty pricey (about $400/GB for installed enterprise class
>storage), the reduction in net required storage puts the basic cost at about $19M.
>Which is, of course a fair chunk higher than the $1.47M of disk on this system.
>
don't know where you are getting the $400 number from. Even the high end is in the 20$ per GB range.


>And a question is whether or not enterprise class SSD is really the correct benchmark
>here. After all, the disk system on this server is using midrange arrays and SAS,
>not FC, disks.

SAS vs FC will make no difference in this case, and SAS IS the new high end. FC is dead as a disk interface. Has no advantage over SAS, much higher cost and no flexibility to use NL/SATA drives in the same array.


>Actual SAS (as opposed to SATA) SSDs will be a bit more, but that’s basically a
>software change in the drive. And that’s not going to produce much of a performance
>change.

SAS only really offers increased reliability due to dual controller functionality, not increased performance over enterprise SATA. They are specifically designed to be intermixed.


>*The server in question is configured with eight dual channel 4Gb FC HBAs, which
>has a maximum theoretical throughput of 12.8GB/s, and the actual sustained rate is going to be rather less than that.
>

I would be surprised if they needed much more than 3-4 GB/s of disk bandwidth.


>**Imation Pro 7000s in that size are showing 1-3 day delivery for $1320 at CDW, for example.
>

Imation Pros would be a very poor choice for this application, their random write IOPS are rather poor and there are several vendors who have better random read IOPS performance.

Will be interesting what price intel/micron will end up selling their high devices at.

Aaron Spink
speaking for myself inc.