[tor-relays] how sensitive is relay 'state' file?

Can anyone comment on how sensitive the information in the relay 'state' is? In particular, if entry guards are recorded in the file should one be concerned about protecting the file via

a) encrypting the file system where it resides

b) making a point of not backing up the file

I suppose it comes down to how likely it is that an adversary can use entry guard information for correlation attacks against past and present tor-client traffic originating from a targeted client-relay.