improve documentation and defaults

diff --git a/README b/README
index 4e42438..5765b93 100644 (file)
--- a/README
+++ b/README
@@ -2,19 +2,27 @@ Ganet extstorage provider for local zfs volumes
 
 INSTALLATION
 
+On node which has zfs storage pool
+
   cd /usr/share/ganeti/extstorage/
   git clone https://github.com/ffzg/ganeti-extstorage-zfs zfs
+  cd zfs
+  vi defaults.sh
+
+You need to specify zfs filesystem under which block devices will be created.
+
+Now ssh into ganeti master node and do following:
 
-  # enable new disk template
+1. enable new disk template
 
   gnt-cluster modify --enabled-disk-templates plain,drbd,ext \
        --ipolicy-disk-templates plain,drbd,ext
 
-  # create log directory
+2. create log directory
 
   mkdir /var/log/ganeti/extstorage
 
-  # try instance creation with something similar to
+3. try instance creation with something similar to
 
   gnt-instance add -t ext --disk=0:size=10G,provider=zfs \
        --disk=1:size=20G,provider=zfs \

diff --git a/defaults.sh b/defaults.sh
index 7c44b7e..28c3173 100644 (file)
--- a/defaults.sh
+++ b/defaults.sh
@@ -1,6 +1,9 @@
 
-# pool and path where to create block devices
+# zfs pool and file system (existing) where to create block devices
 test -z "$EXTP_BLOCK" && EXTP_BLOCK=tmp500g/block
 
-# parameters for zfs create
+# parameters for zfs create, by default
+# -s   sparse
+# -b 4k        block size sutable for ext4 filesystem which ganeti uses
+# lz4  compression with low cpu operhead which always helps
 test -z "$EXTP_VOL_PARAM" && EXTP_VOL_PARAM="-s -b 4k -o compression=lz4"