Feature Name SSD cache
Summary
Using recent kernel (3.9 and later) features for (fast) SSD caching of (slow) ordinary hard disks.
Owner
- Name: Rolf Fokkens
- Email: rolf@rolffokkens.nl
Current status
- Targeted release: Fedora 20
- Last updated: 20130523
- Percentage of completion: 0%
Detailed Description
Recent Linux kernels support the use of Solid State Drives as caches for rotational hard disks. Because the high cost per GB for SSD devices this feature may bring the best of both: fast end big yet affordable storage capacity. Linux kernel 3.9 introduced dm-cache, kernel 3.10 introduces bcache.
Benefit to Fedora
In general operating systems increasingly (will) support SSD caching, because of it's value to users: an affordable solution for both fast and large storage.
Scope
Several tools are in scope:
- Dracut (to support SSD caching for root FS)
- Anaconda (to support SSD caching in clean installs)
- bcache-tools (a new package to support bcache)
- udev (for auto detection of bcache devices)
How To Test
User Experience
Users will experience improved disk performance without explicitly having to decide what to store an fast and what to store on slow media.
Dependencies
This feature relies on the packages as mentioned below:
| Component | Details |
|---|---|
| anaconda | cache handling during install is needed |
| dracut | cache handling during boot is needed |
| bcache-tools | software can be downloaded here and here |
| kernel | Some background info |
| udev | integration in udev |
Contingency Plan
None necessary, revert to previous release behaviour.
Documentation
The feature is very new, some documentation is in the kernel sources.
Here are some links to dm-cache and bcache