On 12-8-2010 2:53 gnuoytr@xxxxxxx wrote:
- The value of SSD in the database world is not as A Faster HDD(tm). Never was, despite the naive' who assert otherwise. The value of SSD is to enable BCNF datastores. Period. If you're not going to do that, don't bother. Silicon storage will never reach equivalent volumetric density, ever. SSD will never be useful in the byte bloat world of xml and other flat file datastores (resident in databases or not). Industrial strength SSD will always be more expensive/GB, and likely by a lot. (Re)factoring to high normalization strips out an order of magnitude of byte bloat, increases native data integrity by as much, reduces much of the redundant code, and puts the ACID where it belongs. All good things, but not effortless.
It is actually quite common to under-utilize (short stroke) hard drives in the enterprise world. Simply because 'they' need more IOps per amount of data than a completely utilized disk can offer. As such the expense/GB can be much higher than simply dividing the capacity by its price (and if you're looking at fiber channel disks, that price is quite high already). And than it is relatively easy to find enterprise SSD's with better pricing for the whole system as soon as the IOps are more important than the capacity.
So in the current market, you may already be better off, price-wise, with (expensive) SSD if you need IOps rather than huge amounts of storage. And while you're in both cases not comparing separate disks to SSD, you're replacing a 'disk based storage system' with a '(flash) memory based storage system' and it basically becomes 'A Faster HDD' ;) But you're right, that for data-heavy applications, completely replacing HDD's with some form of SSD is not going to happen soon, maybe never.
Best regards, Arjen -- Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
