Can flashcache works with DRBD.

[liudan4learn]

I'm trying to use flashcache with DRBD,and just replicate the cache info. but the following problem occurs:

--About hardware configuration--
2 host CentOS7.1 (linux kernel 3.10)
DRBD version: 8.4.6
Flashcache: the lastest version
CacheDevice using ramdisk instead of ssd ,such as /dev/ram0.

--The problem is---
If flashcache volume is created, then 'drbdadm up ' failed to executed with error ''Open(/dev/ram0) failed:Device or Resource busy".
If 'drbdadm up ' is executed, then flashcache volume failed to create with error "device-mapper: reload ioctl on failed:Device or Resource busy".

Then i want to know if flashcachecan work fine with DRBD. If can. how to resolve this problem.
thank you!