This is a bit misleading. ZK is always reliable regardless of disk latency. All that happens on a busy disk is that you get longer latency for ZK transactions. For a dedicated and well-configured machine, you can have average latency (including committing to disk) of about 7 ms. For a multi-purpose busy machine, you may see latencies of 300 ms.
Neither case will cause unreliable operation. On Wed, Dec 8, 2010 at 10:14 AM, Jean-Daniel Cryans <[email protected]>wrote: > Basically, ZK simply needs the lowest latency to disk and network in > order to work reliably. It's not CPU intensive, and it's only memory > intensive if you are using tons of znodes (HBase doesn't). >
