added migrate time

[tridge/hacksm.git] / README

diff --git a/README b/README
index e71d64bad28a04fa239f0509520317b22133bf2e..4c06111503a1ac1f433616e2e57a7a8b44ebf079 100644 (file)
--- a/README
+++ b/README
@@ -10,3 +10,11 @@ Then start the HSM daemon like this:
 
 You can then migrate files using hacksm_migrate, and view their state
 using hacksm_ls
+
+The "store" for hacksm is just a directory with files named by device
+and inode number. When a file is migrated the data is moved to the
+store and a dmapi hole is punched in the original file. This mimicks
+the behaviour of real HSM daemons. When the hacksmd daemon gets a data
+event (indicating that someone wants to read or write the data in the
+file) then the data is restored from the "store" and the file can then
+be read normally.