[OSM-dev] 0.6 move and downtime (re-scheduled)

[Stefan de Konink]

Iván Sánchez Ortega wrote:
> El Viernes, 13 de Marzo de 2009, Stefan de Konink escribió:
>> [...] Therefore your seek times will only decrease if you can search on the 
>> individual disk not as a combined pair.
> 
> I actually wonder what the DB performance could be with some of those new 
> shiny SSD drives... 
> 
> (And how expensive would be to outfit the DB server with a set of them)

That is a thing that was benchedmarked by some people a few weeks ago 
over here. The main problem with even the most expensive SSD disks now, 
that some companies want to hide very much, is the performance hit you 
will get after block shuffling takes places.

It is basically a method to prevent a system to kill a specific piece of 
RAM because it is rewritten again and again. Next to this rewriting will 
generate a block of a length far beyond your wildest dreams to be 
rewritten after one bit changes.


Now the first time you will run bonnie++ you will see average to great 
performance depending what you expect on seek times. (Some people are 
lucky with NetApps or Sun Storage series) But if you run this test on 
the same disk after lets say about one month of usage the performance 
significantly decreased.

...that is odd right.


I hope this issue will be fixed within a few iterations, for now, my 
advise and some commercial users in The Netherlands advice: ditch SSD 
for now, will see if it works later.


Stefan