While I was waiting for nginx and above all PHP1 to compile, I was reading some documentation on LVM and found this little gem:
LVM has now implemented MD software RAID directly also for mirroring, so there is now theoretically no reason to combine the two one on top of the other. You can just create e.g. a RAID1 mirror directly in LVM or convert an existing LVM mirror LV into one.
Apart from LVM’s new RAID implementations not being cluster-aware, there are apparently no drawbacks, only RAID and LVM benefits put together. So it should be stable, easily resizable and surviving the demise of a disk, as well as have some performance gains. You can read more about it on the official LVM RAID documentation.
I converted my LVs from LVM mirror to LVM RAID1 and so far it works fine. There seems to be a slight performance increase as well.
All it takes is:
lvconvert --type raid1 my_vg/my_lv
You can run it also on a mounted LV and it is very fast. Then you will see the
m that represent your LVM mirrors change to
r that represent RAID LVM mirrors, when you run
Caveat: If you want to boot from such a mirror, you need to make sure your kernel includes RAID1 support. Precomplied kernels that come with your distro usually do, but do keep it in mind.
hook out → so far also Pelican seems to be quite nice