BSDCan2016 - v1.1.24a
BSDCan 2016
The Technical BSD Conference
| Speakers | |
|---|---|
|
Matt Ahrens |
| Schedule | |
|---|---|
| Day | Talks #1 - 10 June - 2016-06-10 |
| Room | DMS 1160 |
| Start time | 16:00 |
| Duration | 01:00 |
| Info | |
| ID | 710 |
| Event type | Lecture |
| Track | Invited Talks |
| Language used for presentation | English |
OpenZFS space allocation
doubling performance on large and fragmented pools
Allocating space for new blocks is at the heart of every filesystem, but this is especially true for OpenZFS, because it allocates new blocks for every write, and because blocks are arbitrarily sized. This talk is an overview of how OpenZFS allocates space, including the on-disk data structures used to keep track of where the free space is, and the algorithms used to select the “best” free space to use for a write.
The talk also covers recent improvements to space allocation algorithms, including:
Big wins on pools with “unbalanced” vdevs which have different amounts of free space
A new on-disk data structure which vastly reduces the I/O overhead of tracking free space
Improved diagnosability of the space allocation process