On Fri, Jan 22, 2016 at 4:54 PM, Ed Heron <Ed at heron-ent.com> wrote: > Yes, but it isn't that simple. One copy of the mirror would be on a > physical disk. The other copy of the mirror would be on RAM disk. > Since data in RAM doesn't generally survive reboot, the RAM piece would > need to be turned off before shutdown and created on startup. > >> Is there something about LVM mirroring that can handle disks of >> different speeds? > > With newer LVM, there appears to be some settings that might help with > that a bit. With this older verion, I'd be hoping that the next > available disk would handle each request. If the physical disk takes > longer to deal with the writes, the RAM disk might be the one that is > available most of the time. > > I'd much prefer a method of pre-filling a 35G cache but I saw a > reference to creating a disk mirror in RAM and decided to explore it. > Can you post the results of your test when you get it working?