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Persistent Memory Characteristics
As with every new technology, there are always new things to consider. Persistent
memory is no exception. Consider these characteristics when architecting and
developing solutions:
• Performance (throughput, latency, and bandwidth) of persistent
memory is much better than NAND but potentially slower than
DRAM.
• Persistent memory is durable unlike DRAM. Its endurance is usually
orders of magnitude better than NAND and should exceed the
lifetime of the server without wearing out.
• Persistent memory module capacities can be much larger than
DRAM DIMMs and can coexist on the same memory channels.
• Persistent memory-enabled applications can update data in place
without needing to serialize/deserialize the data.
• Persistent memory is byte addressable like memory. Applications
can update only the data needed without any read-modify-write
overhead.
• Data is CPU cache coherent.
• Persistent memory provides direct memory access (DMA) and
remote DMA (RDMA) operations.
• Data written to persistent memory is not lost when power is removed.
• After permission checks are completed, data located on persistent
memory is directly accessible from user space. No kernel code, file
system page caches, or interrupts are in the data path.
Chapter 2 persistent MeMory arChiteCture