cap: All content tagged as cap in NoSQL databases and polyglot persistence
James Mickens in “The saddest moment“:
In conclusion, I think that humanity should stop publishing papers about Byzantine fault tolerance. I do not blame my fellow researchers for trying to publish in this area, in the same limited sense that I do not blame crackheads for wanting to acquire and then consume cocaine. The desire to make systems more reliable is a powerful one; unfortunately, this addiction, if left unchecked, will inescapably lead to madness and/or tech reports that contain 167 pages of diagrams and proofs. Even if we break the will of the machines with formalism and cryptography, we will never be able to put Ted inside of an encrypted, nested log, and while the datacenter burns and we frantically call Ted’s pager, we will realize that Ted has already left for the cafeteria.
One of the shortest and delightful articles about the complexity of distributed systems.
Now I’ve had a chance to see live Kyle Kingsbury’s “Partitions for Everyone!” presentation at Cassandra SF meetup. The majority of good presentations can be characterized as highly informative or very entertaining. But “Partitions for Everyone!” is one of those rare ones that is both entertaining and informative.
InfoQ has the video of Kyle Kingsbury’s presentation at strangeloop 2013. Take the 45 minutes to watch it!
Original title and link: Aphyr’s Partitions for Everyone presentation ( ©myNoSQL)
Thanks to Murat Demirbas, I got a link to the SOSP‘13 papers. Maybe is because of my myopic interest, but it seems like quite a few papers this year were focus on the topic of transactions and consistency:
- Speedy Transactions in Multicore In-Memory Databases by Stephen Tu, Wenting Zheng (MIT), Eddie Kohler (Harvard), Barbara Liskov, Samuel Madden (MIT)
- From ARIES to MARS: Transaction Support for Next-Generation, Solid-State Drives by Joel Coburn, Trevor Bunker, Meir Schwarz, Rajesh K. Gupta, Steven Swanson (University of California, San Diego)
- Transaction Chains: Achieving Serializability with Low Latency in Geo-Distributed Storage Systems1 by Yang Zhang, Russell Power, Siyuan Zhou, Yair Sovran (NYU), Marcos K. Aguilera (Microsoft Research), Jinyang Li (NYU)
- Consistency-Based Service Level Agreement for Cloud Storage by Douglas B. Terry, Vijayan Prabhakaran, Ramakrishna Kotla, Mahesh Balakrishnan, Marcos K. Aguilera (Microsoft Research), Hussam Abu-Libdeh (Cornell University)
- Everything You Always Wanted to Know about Synchronization but Were Afraid to Ask by Tudor David, Rachid Guerraoui, Vasileios Trigonakis (EPFL)
This SOSP‘13 page has download links for all papers.
Original title and link: Papers on transactions and consistency from SOSP’13 ( ©myNoSQL)
The recent announcement of the Microsoft SQL Server 2012 release emphasized the high availability features added to this version. Here is what I could find after some digging through the documentation:
AlwaysOn Failover Cluster Instances: As part of the SQL Server AlwaysOn offering, AlwaysOn Failover Cluster Instances leverages Windows Server Failover Clustering (WSFC) functionality to provide local high availability through redundancy at the server-instance level—a failover cluster instance (FCI). An FCI is a single instance of SQL Server that is installed across Windows Server Failover Clustering (WSFC) nodes and, possibly, across multiple subnets. On the network, an FCI appears to be an instance of SQL Server running on a single computer, but the FCI provides failover from one WSFC node to another if the current node becomes unavailable.
This is explained in more detail on AlwaysOn Failover Cluster Instances (SQL Server).
AlwaysOn Availability Groups: The AlwaysOn Availability Groups feature is a high-availability and disaster-recovery solution that provides an enterprise-level alternative to database mirroring. Introduced in SQL Server 2012, AlwaysOn Availability Groups maximizes the availability of a set of user databases for an enterprise. An availability group supports a failover environment for a discrete set of user databases, known as availability databases, that fail over together. An availability group supports a set of read-write primary databases and one to four sets of corresponding secondary databases. Optionally, secondary databases can be made available for read-only access and/or some backup operations.
More documentation about AlwaysOn Availability groups can be found here.
Database mirroring: This feature will be removed in a future version of Microsoft SQL Server.
Log shipping: SQL Server Log shipping allows you to automatically send transaction log backups from a primary database on a primary server instance to one or more secondary databases on separate secondary server instances.
This is the well-known master-slave setup. More details can be found here.
Also worth checking the availability of these feature per SQL Server 2012 editions:
Original title and link: Microsoft SQL Server 2012 High Availability Solutions ( ©myNoSQL)