OpenStack Summit October 2015 Tokyo

Shingled magnetic recording (SMR) drives have the potential to significantly reduce storage costs. However, they have very different characteristics than standard drives. In this talk we will give background information on SMR drives and talk about performance of both device-managed (use firmware to hide differing characteristics) and host-managed (rely on the application to manage the differing characteristics) SMR drives under various simulated Swift workloads modeled after public cloud access patterns observed at SoftLayer.
 
We also present a simulation of what performance would be possible if Swift's DiskFile abstraction was modified to be SMR aware by performing sequential writes, a key requirement for utilizing SMR disks. We then discuss methods to optimize Swift deployments for SMR drives.

The session will highlight:
- Background information on SMR drives and their management models
- Experiments to characterize SMR drive performance
- How to tune Swift to improve performance with SMR drives
- Potential Swift changes to enable sequential writes that would enable better usage of SMR drives and expected performance