LVM2 has supported the creation of cache LVs for some time, but that feature requires that it is built with the `--with-cache=internal' configure option. While this is a somewhat experimental feature, there are many references to its existence in both the lvm(8) man page and the help output of some utilities e.g. `lvconvert --help', even when it is disabled. Building LVM2 with this option would allow testers to try out this feature, without requiring a special build of LVM2 - AFAIK it is already enabled by default in at least Debian Testing and Redhat/Centos 7.
Keywords: (none) => TriagedAssignee: bugsquad => tmb
I converted my Cauldron root filesystem to lvmcache. Performance-wise it seems to be worth it, even in the default write-through mode. That said, I had to jump through a few hoops: - I updated the LVM2 package to version 2.02.114, which enables lvmcache by default and fixes quite a few things. - I compiled and installed the thin-provisioning-tools package (https://github.com/jthornber/thin-provisioning-tools) - see below. - I modified the dracut configuration to include the thin-provisioning-tools binaries in the initramfs, using the `install_items+=...' option. Without this modification the system would not boot, because lvm2 requires these binaries when a thin or cached LV exists. - I regenerated the initramfs and ran `lilo' to update the bootloader - GRUB users would not need this step. All in all, it still seems quite easy to shoot yourself in the foot with lvmcache. The LVM2 people are making good progress w.r.t. making things safer, but it's probably not for the faint-hearted just yet.
Thomas, this is done by other distros, eg: Fedora. I think it's safe to add --with-cache=internal Though it's now the default, so we can close this bug as OLD
Resolution: (none) => OLDCC: (none) => thierry.vignaudStatus: NEW => RESOLVED