docs: add docs for cephfs

- specifically related to managing csi volumes for kubernetes

doc/ceph/README.md

@@ -33,12 +33,32 @@ Always refer back to the official documentation at https://docs.ceph.com/en/late
 
 This will:
 
-    Create erasure code profiles. The K and M values are equivalent to the number of data disks (K) and parity disks (M) in RAID5, RAID6, etc.
-    Create data pools using the erasure-code-profile, set some required options
-    Add the pool to the fs `cephfs`
-    Create a subvolumegroup using the new data pool
+Create erasure code profiles. The K and M values are equivalent to the number of data disks (K) and parity disks (M) in RAID5, RAID6, etc.
 
+    sudo ceph osd erasure-code-profile set ec_6_2 k=6 m=2
+    sudo ceph osd erasure-code-profile set ec_4_1 k=4 m=1
 
+Create data pools using the erasure-code-profile, set some required options
+
+    sudo ceph osd pool create cephfs_data_ssd_ec_6_2 erasure ec_6_2
+    sudo ceph osd pool set cephfs_data_ssd_ec_6_2 allow_ec_overwrites true
+    sudo ceph osd pool set cephfs_data_ssd_ec_6_2 bulk true
+
+    sudo ceph osd pool create cephfs_data_ssd_ec_4_1 erasure ec_4_1
+    sudo ceph osd pool set cephfs_data_ssd_ec_4_1 allow_ec_overwrites true
+    sudo ceph osd pool set cephfs_data_ssd_ec_4_1 bulk true
+
+Add the pool to the fs `cephfs`
+
+    sudo ceph fs add_data_pool cephfs cephfs_data_ssd_ec_6_2
+    sudo ceph fs add_data_pool cephfs cephfs_data_ssd_ec_4_1
+
+Create a subvolumegroup using the new data pool
+
+    sudo ceph fs subvolumegroup create cephfs csi_ssd_ec_6_2 --pool_layout cephfs_data_ssd_ec_6_2
+    sudo ceph fs subvolumegroup create cephfs csi_ssd_ec_4_1 --pool_layout cephfs_data_ssd_ec_4_1
+
+All together:
 
     sudo ceph osd erasure-code-profile set ec_6_2 k=6 m=2
     sudo ceph osd pool create cephfs_data_ssd_ec_6_2 erasure ec_6_2