bcache-tools and bcache support in other linux packages
rolf at rolffokkens.nl
Thu Sep 26 09:56:25 UTC 2013
Like I did on the 14th on the linux-bcache list I'd like to send an
update on the progress of bcache related packages. While focussing on
Fedora packaging of bcache-tools, I had some good collaboration with
other packagers resulting in improved bcache support in other packages
as well. Other Linux distro's may benefit from these updated packages too.
On 27th of September util-linux v2.24 RC will probably be released. This
release supports the identification of bcache superblocks in libblkid,
actually integrating and obsoleting probe-bcache. Because of this udev
rules for bcache can be simplified because they only need blkid. Of
course this only applies to systems where util-linux v2.24 RC (or
higher) actually is installed, otherwise probe-bcache is still needed.
Since version 032 Dracut already had bcache support. Since version 033
it adds support for util-linux v2.24 RC, so even without (obsoleted)
probe-bcache it is able to identify bcache using blkid. Additionally
Dracut benefits from blkid being able to identify bcache, because it
uses blkid to identify all necessary kernel modules automatically, so no
-N option is needed anymore.
With the release of v2_01_102 LVM2 now accepts Physical Volumes on
bcache by default. This simplifies the creation of initramfs (by Dracut)
because no specific LVM2 option (--lvmconf) needs to be passed to
Dracut.For the user this means that updating a kernel just works out of
The bcache-tools package is available in Fedora 20. I plan to build an
updated package that no longer includes probe-bcache when the new
util-linux is released.
Anaconda (the Fedora installer) does not support bcache yet. This is
planned for Fedora 20. This is important when installing Fedora on a
system and having your root filesystem on bcache. Althought other
Distro's don't use Anaconda, I guess their installers also need to be
changed in some way to supportbcache.
Currently having Fedora installed with your root Filesystem on bcache is
possible, but It's done in a fewsteps:
1. Install Fedora using Anaconda without using bcache, but create an
extra partition to supportan alternate root FS
2. From the running system build a bcache device using the extra
partition. Copy the current root FS to the bcache root FS
3. Reboot your system in the bcache root FS, and reclaim the spaces used
by the non-bcache root partition
More information can be found below, related to the "SSD Cache Fedora
The SSD Cache Fedora test day
On 13th of October there's an "SSD Cache Fedora test day": see the Wiki
page https://fedoraproject.org/wiki/Test_Day:2013-10-13_SSD_Cache. This
page is work in progress, any feedback is welcome. People interested in
testing are invited to participate on 13th of October.
When there's anything new toreport, I'll keep you posted.
More information about the devel