Changes between Version 1 and Version 2 of ESGFPublicationZFS

Timestamp:

Jun 6, 2017 4:10:15 PM (4 years ago)

Author:

zequi

Comment:

--

ESGFPublicationZFS

@@ -3 +3 @@
 Institutions store their datasets in different formats according to their own needs. Publication to projects, such as CORDEX, require from common formats that datasets must follow. Here we present a use case of ZFS to prepare data for publication.
 
-= Background =
+== Background ==
 
 Suppose that we have a zfs like this:
@@ -18 +18 @@
 == ZFS snapshots and clones ==
 
+In first place, we would create a snapshot of the filesystem. This would not have any additional cost, since zfs snapshots only require disk space if the files are modified.
+
+{{{
+# zfs snapshot tank/test/datasetA@today
+# zfs list -r tank/test
+NAME                       USED  AVAIL  REFER  MOUNTPOINT
+tank/test                  104M  66.2G    23K  /tank/test
+tank/test/datasetA         104M  66.2G   104M  /tank/test/productA
+tank/test/datasetA@today      0      -   104M  -
+}}}
+
+Now, we can change dataset attributes, for example, via ncatted and we would have two datasets: the modified one "tank/test/datasetA" and the legacy one "tank/test/datasetA@today" having required only the disk space for the original dataset.
+
+We also can make clones of the {{{tank/test/datasetA@today}}} in order to modify the legacy dataset, since zfs snapshots are read-only filesystems.
+
+{{{
+# zfs clone tank/test/datasetA@today tank/test/datasetA
+# zfs list -r tank/test
+NAME                       USED  AVAIL  REFER  MOUNTPOINT
+tank/test                  104M  66.2G    23K  /tank/test
+tank/test/datasetA         104M  66.2G   104M  /tank/test/datasetA
+tank/test/datasetA@today      0      -   104M  -
+tank/test/datasetAClone       0  66.2G   104M  /tank/test/datasetAClone
+}}}
+
+This clone can be promoted in case we need to use the legacy dataset again.
+
+{{{
+# zfs promote tank/test/datasetAClone
+# zfs list -r tank/test
+NAME                       USED  AVAIL  REFER  MOUNTPOINT
+tank/test                  104M  66.2G    23K  /tank/test
+tank/test/datasetA            0  66.2G   104M  /tank/test/datasetA
+tank/test/datasetA@today      0      -   104M  -
+tank/test/datasetAClone    104M  66.2G   104M  /tank/test/datasetAClone
+}}}
+
+For more information see http://docs.oracle.com/cd/E19253-01/819-5461/gbcxz/index.html.