A week’s worth of posts for you

I can’t keep up with all the things to post.  I desperately want to clear my inbox, so here’s a week’s worth of posts all smushed together.  Enjoy!

Phew.

Cache-data-as-swap project started

Matthew Dillon is setting up DragonFly to be able to use a fast disk (like a SSD) for disk cache, reducing the effect swap has on speed.  This means very large amounts of data could be read into memory – greater than the available RAM in the system – without having the normal paging out problems that happen when memory is exhausted.   It’ll work for any filesystem on the machine – HAMMER, UFS, or NFS.  His inital notes have more.  Other notes include details on the NFS benefits, and possibilities with SSDsWear-leveling may make SSDs last much longer.

Work has started, and there’s an update (with examples) that people can try, though it may destroy all your data at this point.  Test results in that update show, if I’m reading it right, a better than doubling of speed on a repeated md5 test on a large file when using the new caching system.  This should be a huge benefit.

Hammer REDO and other storage notes

Matthew Dillon declared his intention to have REDO working for Hammer very soon.  This will improve speed by lowering the number of fsync()s needed in a given period of time to flush data to disk.

He continues in a separate message talking at length about data flushing and how to implement it efficiently, with some comparisons to work in FreeBSD.  The followups are worth reading, too.

Using NVIDIA on DragonFly

This has been around for a while, but I’m re-mentioning it because it’s not really linked anywhere: Simon ‘corecode’ Schubert has a version of the FreeBSD NVIDIA video driver that should work on DragonFly: http://gitweb.dragonflybsd.org/~corecode/nvidia.git.  It should be possible to clone from that link, build the code, and use it.  (Untested by me – if you’ve done it, some explicit instructions would be helpful to others.)