On Fri, Jan 22, 2016 at 4:54 PM, Ed Heron Ed@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?