Forum: VoltDB Architecture

Post: Can VoltDB truly claim the 'D' in ACID ?

Can VoltDB truly claim the 'D' in ACID ?
gambitg
Oct 21, 2010
VoltDB writes to disks asynchronously (either though export or through backups). In my test where I have exports switched on and I 'pull the plug' on the database server (simulation of catastrophic data center events)., last 300ms (approx) of 'committed data' does not make to the export log.
Of course I did not have BBUs and SSDs, which can reduce the frequency/exposure-window of 'pull the plug' scenario. Still there is a possibility (however slim) of 'committed data' not making to disk.
(I did not try multiple clusters but those are also asynchronously committed to some other geographic location, so the exposure window should be larger than a local disk export)


Can the durability be claimed for critical OLTP apps (say banking) ?
re: Can VoltDB truly claim the 'D' in ACID ?
tcallaghan
Oct 21, 2010
Gambitg,


VoltDB is durable through k-safety. When starting a VoltDB cluster you choose the value of k, and VoltDB stores k+1 copies of all data on different physical servers. Every transaction commits to all (k+1) partitions before returning success to the user.


The other options you mention, export and snapshots, are additional features of VoltDB. They can both be part of a backup/recovery strategy but providing durability was not their goal.


-Tim