HeRMES: High-Performance Reliable MRAM-Enabled Storage

Appeared in Proceedings of the 8th IEEE Workshop on Hot Topics in Operating Systems (HotOS-VIII).


Magnetic RAM (MRAM) is a new memory technology with access and cost characteristics comparable to those of conventional dynamic RAM (DRAM) and the non-volatility of magnetic media such as disk. Simply replacing DRAM with MRAM will make main memory non-volatile, but it will not improve file system performance. However, effective use of MRAM in a file system has the potential to significantly improve performance over existing file systems. The HeRMES file system will use MRAM to dramatically improve file system performance by using it as a permanent store for both file system data and metadata. In particular, metadata operations, which make up over 50% of all file system requests [14], are nearly free in HeRMES because they do not require any disk accesses. Data requests will also be faster, both because of increased metadata request speed and because using MRAM as a non-volatile cache will allow HeRMES to better optimize data placement on disk. Though MRAM capacity is too small to replace disk entirely, HeRMES will use MRAM to provide high-speed access to relatively small units of data and metadata, leaving most file data stored on disk.

Publication date:
May 2001

Ethan L. Miller
Scott A. Brandt
Darrell D. E. Long

Storage Class Memories

Available media

Full paper text: PDF

Bibtex entry

  author       = {Ethan L. Miller and Scott A. Brandt and Darrell D. E. Long},
  title        = {{HeRMES}: High-Performance Reliable {MRAM}-Enabled Storage},
  booktitle    = {Proceedings of the 8th IEEE Workshop on Hot Topics in Operating Systems (HotOS-VIII)},
  pages        = {83-87},
  month        = may,
  year         = {2001},
Last modified 5 Aug 2020