diff --git a/doc/internals.mdwn b/doc/internals.mdwn
index 27b5bb1f29..1096845e5e 100644
--- a/doc/internals.mdwn
+++ b/doc/internals.mdwn
@@ -21,8 +21,8 @@ deleting or changing the file contents.
 
 This branch is managed by git-annex, with the contents listed below.
 
-The file `.git/index.git-annex` is a separate git index file it uses
-to accumlate changes for the branch. Also, `.git/annex/journal/` is used
+The file `.git/annex/index` is a separate git index file it uses
+to accumlate changes for the git-annex. Also, `.git/annex/journal/` is used
 to record changes before they are added to git.
 
 Note that for speed reasons, git-annex assumes only it will modify this
diff --git a/doc/upgrades.mdwn b/doc/upgrades.mdwn
index 509e296956..1813d079a1 100644
--- a/doc/upgrades.mdwn
+++ b/doc/upgrades.mdwn
@@ -32,6 +32,9 @@ After the upgrade is complete, commit the changes it staged.
 	
 	git commit -m "upgrade v2 to v3"
 
+Running `git gc` after this upgrade will likely free up significant disk 
+space. (Tens to hundreds of megabytes.)
+
 ### v1 -> v2 (git-annex version 0.20110316)
 
 Involved adding hashing to .git/annex/ and changing the names of all keys.