Scalability updates for Aug 27th 2010

My updates have been slow recently due to other things I’m involved in. If you need more updates around what I’m reading, please feel free to follow me on twitter or buzz.

Here are some of the big ones I have mentioned on my twitter/buzz feeds.

Scalability links for March 20th 2010 – Lots of datastore related items

Scalability links for March 13th 2010

For some reason there has been a disproportionately high number of news items on Cassandra lately. Some of those are included below, but also included are some other interesting updates which you might have missed.

Cassandra

Scalability links for Feb 28th 2010

SimpleDB now allows you to tweak consistency levels

We discussed Brewer’s Theorm a few days ago and how its challenging to obtain Consistency, Availability and Partition tolerance in any distributed system. We also discussed that many of the Amazon Web Servicesdistributed datastores allow CAP to be tweaked to attain certain operational goals.

Amazon SimpleDB, which was released as an “Eventually Consistent” datastore,  today launched a few features to do just that.

  • Consistent reads: Select and GetAttributes request now include an optional Boolean flag “ConsistentRead” which requests datastore to return consistent results only. If you have noticed scenarios where read right after a write returned an old value, it shouldn’t happen anymore.
  • Conditional put/puts, delete/deletes : By providing “conditions” in the form of a key/value pair SimpleDB can now conditionally execute/discard an operation. This might look like a minor feature, but can go a long way in providing reliable datastore operations.

Even though SimpleDB now enables operations that support a stronger consistency model, under the covers SimpleDB remains the same highly-scalable, highly-available, and highly durable structured data store. Even under extreme failure scenarios, such as complete datacenter failures, SimpleDB is architected to continue to operate reliably. However when one of these extreme failure conditions occurs it may be that the stronger consistency options are briefly not available while the software reorganizes itself to ensure that it can provide strong consistency. Under those conditions the default, eventually consistent read will remain available to use.

References

Scalability updates for Feb 18, 2010

Some of interesting links for today

Scalability Updates for Jan 26th 2010

A few interesting updates for today