Until very recently, I was a bit puzzled by the Table Storage. I couldn't manage to get a clear understanding how the Table Storage could be a killer option against the Blob Storage.
I get it now: Table Storage can cut your storage costs by 100x.
At outlined by other folks already, I/O costs typically represents more than 10x the storage costs if your objects are weighting less than 6kb (the computation has been done for the Amazon S3 pricing, but the Windows Azure pricing happens to be nearly identical).
Thus, if you happen to have loads of fine grained objects to store in your cloud, say less-than-140-characters tweets for example, you're likely to end-up with an insane I/O bill if you happen to store those fine-grained items in the Blob Storage.
But don't lower your hopes, that's precisely the sort of situations the Table Storage has been designed for, as this service lets you insert/update/delete entities by batches of 100 through Entity Group Transactions.
This fine-grained item orientation is reflected in the limitations that apply to entities:
- A single entity should not weight more than 1MB.
- A single group transaction should not weight more than 4MB.
- A single entity property should not weight more than 64kb.
Situations where loads of small items end-ups being processed - threshold being at 60kb - by your cloud apps are likely to be good candidate for the Table Storage.
We will definitively try to reflect this in our favorite O/C mapper.