[linux-lvm] Network-attached block storage and local SSDs for dm-cache

[Konstantin Ryabitsev]

Hi, all:

I know it's possible to set up dm-cache to combine network-attached 
block devices and local SSDs, but I'm having a hard time finding any 
first-hand evidence of this being done anywhere -- so I'm wondering if 
it's because there are reasons why this is a Bad Idea, or merely because 
there aren't many reasons for folks to do that.

The reason why I'm trying to do it, in particular, is for 
mirrors.kernel.org systems where we already rely on dm-cache to combine 
large slow spinning disks with SSDs to a great advantage. Most hits on 
those systems are to the same set of files (latest distro package 
updates), so dm-cache hit-to-miss ratio is very advantageous. However, 
we need to build newest iterations of those systems, and being able to 
use network-attached storage at providers like Packet with local SSD 
drives would remove the need for us to purchase and host huge drive 
arrays.

Thanks for any insights you may offer.

Best,
Konstantin