[patio11]

MemcacheDB periodically flushes its in-memory DB to disk, using BDb. That causes a global read/write lock for a looooong time. (This pauses BCC for 5 seconds at a time when it happens, and I only have 20 MB stored in memcachedb. To rectify this I'm moving to Redis as soon as I get a day free. Suffice it to say that if Bingo Card Creator taxes the architecture of your key/value store, you may not quite be ready for prime time.)

[antirez]

I may be a bit biased, but if what they want is a fast persistent cache Redis should really be a good fit.

[zepolen]

Does Redis block when writing to disk?

[antirez]

No writes are asynchronous.