My target is to install ubuntu with lvmcache, use a ssd drive to speed up system io.
lvmcache pitfalls on ubuntu (2016/02)
- 14.04 lvm2 don't support lvmcache
- 15.04, 15.10 raid cause NMI watchdog: BUG: soft lockup - CPU#0 stuck for 22s! error on my machine by default, system always stucks right after boot
- Failed to boot with lvm2's new default setting cache-policy-smq lvmcache failed to boot: “device-mapper: cache-policy: unknown policy type”
UPDATE 2016/02/18 ubuntu 16.04 has kernel 4.4 to avoid the CPU#0 stuck problem. i am going with 16.04 now.
1. install 16.04 + raid + lvm
2. add lvmcache
Create cache-pool with mq policy until smq is well-supported.
thin-provisioning-tools is needed: it's contain /usr/sbin/cache_check
IF Boot failed: Use ubuntu 16.04 live CD to run boot-repair
16.04 xenial is required if you are using lvmcache