Persistent Memcached: Bringing Legacy Code to Byte-Addressable Persistent Memory


Virendra J. Marathe, Margo Seltzer, Steve Byan, and Tim Harris, Oracle Labs


We report our experience building and evaluating pmemcached, a version of memcached ported to byte-addressable persistent memory. Persistent memory is expected to not only improve overall performance of applications’ persistence tier, but also vastly reduce the “warm up” time needed for applications after a restart. We decided to test this hypothesis on memcached, a popular key-value store. We took the extreme view of persisting memcached’s entire state, resulting in a virtually instantaneous warm up phase. Since memcached is already optimized for DRAM, we expected our port to be a straightforward engineering effort. However, the effort turned out to be surprisingly complex during which we encountered several non-trivial problems that challenged the boundaries of memcached’s architecture. We detail these experiences and corresponding lessons learned.

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@inproceedings {203358,
author = {Virendra J. Marathe and Margo Seltzer and Steve Byan and Tim Harris},
title = {Persistent Memcached: Bringing Legacy Code to {Byte-Addressable} Persistent Memory},
booktitle = {9th USENIX Workshop on Hot Topics in Storage and File Systems (HotStorage 17)},
year = {2017},
address = {Santa Clara, CA},
url = {},
publisher = {USENIX Association},
month = jul