Projects

unburden-home-dir

unburden-home-dir allows users to move cache files from browsers, etc. off their home directory, i.e. on a local harddisk or tmpfs and replace them with a symbolic link to the new location (e.g. on /tmp/ or /scratch/) upon login. Optionally the contents of the directories and files can be removed ... [More] instead of moved. This is helpful for NFS homes, systems with homes on small flash disks or SSDs but with a lot of RAM, and for not cluttering backups of /home/ with cache files. [Less]

disksurvey

Survey Disks for interesting information for the purpose of learning about disk failures

Optimized File system & Platform for

Development of File System and Platform that Optimized for SSDs

cachefs

Abstract The focus of this project is a hybrid file system, with the declared purpose of accelerating file access time and a possible improvement of power usage through the combined usage of random-access memory, solid-state drives and hard disk drives. The idea is simple: use the fast memory (RAM ... [More] and SSD) as a two-level cache. The most accessed files will be stored into RAM, while the medium accessed files will reside in the SSD. When a file is not located into the cache memory, a cache miss event takes place and data is read from the hard drive. By using the SSD as a level 2 cache, large files can be accessed very fast (as compared to the HDD). Large files cannot typically be held into a RAM disk, as its capacity can be easily filled. Current SSD models have capacities of 120 GB and reading speeds of up to 250 MB/s. This is well beyond what a high speed hard drive can offer (Western Digital Velociraptor topping at ~100 MB/s). Performance tuning can be done for specific applications by creating file acces profiles and then storing that data into the cache levels. Also, a library for allowing cache-aware application will be implemented. Power usage improvement is achieved by obtaining a "stable file access profile": all the needed files are located in the RAM and SSD, therefore making it possible to shut down the hard drive in order to save power. The inspiration for this project was the Conquest-2 project at UCLA (http://www.lasr.cs.ucla.edu/Conquest-2.html), which used only RAM and HDD, but employed a more sofisticated file access pattern profiling that what it is planned. Developing team: Ioan Ovidiu Hupca, Ionuț Petre and Alexandru Stan Keywords: filesystem, hybrid, cache, solid-state drive References: 1. Conquest-2, Improving Energy Efficiency and Performance Through a Disk/Hybrid File System 2. The Conquest File System: Better Performance Through a Disk/Persistent-RAM Hybrid Design link1 link2 3. Proceedings of the 2002 USENIX Annual Technical Conference. Conquest: Better Performance Through A Disk/Persistent-RAM Hybrid File System Current development stage: File System driver [Less]

devcache

The devcache project is an attempt to provide a Linux kernel module which allows for any block device to be used as a cache for any other block device. There is a specific focus on using solid-state drives (NAND Flash) as a cache for conventional hard-disk drives. The hope is to have this design ... [More] utilized in computing/disk clusters to increase overall I/O performance. The concept is similar to the Microsoft Windows Vista feature "ReadyBoost", although devcache should be a more generic solution. The actual cache implementation currently supports LRU and MRU evictions policies, and can be a Write-None (read-only) or a Write-Thru cache. It is generic, and can be seperated from devcache and used in other projects, or easily modified. This project is being developed for The George Washington University, ECE 227, Fall 2008. [Less]

flashcache

FlashCache is a general purpose writeback block cache for Linux.

libscsicmd

A library to create SCSI commands (CDBs) and parse the results, also for ATA commands and results

ssdjoin

join algorithms for solid state disk