O'Reilly logo

PostgreSQL 9.0 High Performance by Gregory Smith

Stay ahead with the world's most comprehensive technology and business learning platform.

With Safari, you learn the way you learn best. Get unlimited access to videos, live online training, learning paths, books, tutorials, and more.

Start Free Trial

No credit card required

Filesystem crash recovery

Filesystem writes have two major components to them. At the bottom level, you are writing out blocks of data to the disk. In addition, there is some amount of filesystem metadata involved too. Examples of metadata include the directory tree, the list of blocks and attributes associated with each file, and the list of what blocks on disk are free.

Like many disk-oriented activities, filesystems have a very clear performance vs. reliability trade-off they need to make. The usual reliability concern is what happens in the situation where you're writing changes to a file and the power goes out in the middle.

Consider the case where you're writing out a new block to a file, one that makes the file bigger (rather than overwriting ...

With Safari, you learn the way you learn best. Get unlimited access to videos, live online training, learning paths, books, interactive tutorials, and more.

Start Free Trial

No credit card required