Can Flash wear out? Is there a write limit?

Yes.  However, our Flash-based systems are designed from the Flash chip up to protect applications.  The systems use SLC NAND Flash memory which has the longest write lifecycle of any Flash memory chip with 100,000 writes per block, and each Flash chip has over 16,000 blocks.  We use a RAM cache system to distribute the writes evenly over all the blocks in each Flash chip, and across all the Flash chips in the system.  We also have more Flash memory in the systems than what is reported as usable to spread the writes over more chips.  These functions are called wear leveling.  Our systems are designed so that even under the maximum write load it isn’t possible to wear out the Flash in less than 3 years.  To learn more about the reliability of Flash, read our white paper: Flash Solid State Disk Reliability.