Merge pull request #272 from trapexit/faq-direct-reads

faq update on direct writes

README.md

@@ -1,6 +1,6 @@
 % mergerfs(1) mergerfs user manual
 % Antonio SJ Musumeci <trapexit@spawn.link>
-% 2016-04-25
+% 2016-05-03
 
 # NAME
 
@@ -359,6 +359,10 @@ While aufs can offer better peak performance mergerfs offers more configurabilit
 
 A single drive failure will lead to full pool failure without additional redundancy. mergerfs performs a similar behavior without the catastrophic failure and lack of recovery. Drives can fail and all other data will continue to be accessable.
 
+#### Can drives be written to directly? Outside of mergerfs while pooled?
+
+Yes. It will be represented immediately in the pool as the policies would describe.
+
 #### It's mentioned that there are some security issues with mhddfs. What are they? How does mergerfs address them?
 
 [mhddfs](https://github.com/trapexit/mhddfs) tries to handle being run as **root** by calling [getuid()](https://github.com/trapexit/mhddfs/blob/cae96e6251dd91e2bdc24800b4a18a74044f6672/src/main.c#L319) and if it returns **0** then it will [chown](http://linux.die.net/man/1/chown) the file. Not only is that a race condition but it doesn't handle many other situations. Rather than attempting to simulate POSIX ACL behaviors the proper behavior is to use [seteuid](http://linux.die.net/man/2/seteuid) and [setegid](http://linux.die.net/man/2/setegid), become the user making the original call and perform the action as them. This is how [mergerfs](https://github.com/trapexit/mergerfs) handles things.