General reply
> Was this an advertisement for Teradata?
No, is the simple answer. Teradata didn’t pay for the article, it didn’t even request it. I wrote the article because I have used SSDs is databases and found them efficacious in certain situations, so I wrote about them. Teradata has, in my opinion, an excellent database engine and makes innovative use of SSDs, so I mentioned the company and the product as well.
>Interesting, the format of this piece followed exactly that of Radio Four's "Thought for the Day":
I have to say that I am proud to be even considered in the same breath as Rabbi Bloom......
>Something also tells me that Teradata may not be quite as unique in this as they claim.
Certainly other companies can migrate data dependent upon its use but none, so far as I am aware, do it as effectively as Teradata – which is why I chose that company as the example. .
> What is the basis for that tiny power consumption figure for SSD's?
> And what's the deal with the SSD info? 150mW? Where? Which models?
The figures are for the Intel X18-M and X25-M Mainstream SATA Solid-State Drive. In fact, the figure I quoted was the Active power consumption (150 mW Typical (PC workload); the idle figure is half that (75 mW Typical)
>Then there's the issue of "blistering" speed. Yes, read speed is good,
>but write speed is horrible, especially for random writes.
This certainly used to be true and you may have had poor experiences with early disks, but the most recent SSDs are in a different class.
>The Imation S-Class 27519, for example, has 19,000 random read IOPS
>but only 130 random write IOPS.
>The Intel X-25E has 35,000 random read IOPS but only 3,300 random write IOPS.
True, but the figures for the X 18-M and X 25-M are:
Random I/O Operations Per Second (IOPS) Random 4 KB Reads: up to 35,000 IOPS
Random 4 KB Writes:
• 80 G X25/X18-M - up to 6,600 IOPS
• 160 G X25/X18-M - up to 8,600 IOPS
> Many benchmarks have shown SSDs to be horribly slow at small (4K) writes as well.
Please note that the above figures are for 4K writes.
>So, if you're going to call an SSD "blistering", you better qualify it by saying that it's >only "blistering" for reads, as write speed will likely be far less than even a
>5400-rpm hard drive on a write-heavy basis.
Given the figures quoted above for the new Intel disks, I’m happy that the use of the word ‘blistering’ is still appropriate unqualified.
>"5K rpm" hard disks? Where? When was the last time anyone bought a 5K rpm hard disk? >Searching my distributors, I could only find a few models still available in 5400
>(5900 for a few Seagates) rpm. 7200 rpm has been the standard for a long time.
Where? - Still available at your distributers. When? People are still buying them now. And they are very cheap because, I agree, the standard disk of today is faster. What I was trying to do in this table was to plot the ends of the available disk spectrum. Had I started the table with a 7K RPM disk someone would have pointed out, quite correctly, that 5K RPM disks were still available and I had missed them.
>The best place for hot data is in memory.
For speed certainly, but speed is not the only consideration; Durability is also certainly part of the ACID test....
Biting the hand that feeds IT
