In the last section of this lab, you recovered lost data using zfs snapshot. Now, we will get to know another very useful function of ZFS: filesystem cloning.
2.3. Clone Filesystems using ZFS
Open your browser and navigate to your share.
The fastest way to get there is by clicking shares in the top menu and then do a double click on your share. On the new page, go to snapshot.
To clone your filesystem, you first have to take a snapshot. We already did this in the last section, so you can use this and go straight to the cloning.
Hover with your mouse over mysnap2 and again the three icons should appear on the right side. This time, click the one in the middle (a plus sign).
Enter a name of your choosing and click apply.
And that’s it.
Notice the “1” in the clone column of mysnap2. If you hover over mysnap2, there should appear a show next to this 1. Click on this link to open a popup with information for all the clones of that snapshot.
You can see the entry from the clone, you just created.
Next, go to shares in the top menu and you should see both shares, the original one and the clone.
Notice the mountpoint of the clone, which is automatically set to /export/myclone
also notice the size of the two filesystem. Although both contain exactly the same data, the clone is a lot smaller, than the original. That is because for a clone ZFS stores only those data blocks on disk, that have changed since the clone was taken.
Now, go to your database machine (login as root), open a shell and mount the new share.
[root@localhost ~]# mkdir /mnt/clone mount 192.168.56.100:/export/myclone /mnt/clone/
check, that both mounts are in place
[root@localhost ~]# df -h Filesystem Size Used Avail Use% Mounted on 192.168.56.100:/export/myshare 20G 0 20G 0% /mnt/zfsapp 192.168.56.100:/export/myclone 20G 0 20G 0% /mnt/clone
You should also see the important.txt inside the new share.
[root@localhost ~]# cd /mnt/clone/ [root@localhost clone]# ls -la total 11 drwx------+ 3 nobody bin 3 Aug 19 2013 . drwxr-xr-x 6 root root 4096 Aug 19 04:55 .. -rw-r--r--+ 1 nobody nobody 18 Aug 19 2013 important.txt dr-xr-xr-x+ 4 root root 4 Aug 19 2013 .zfs
[root@localhost clone]# cat important.txt do not loose this
As you can see, this is the same data, as in the original filesystem.
That concludes the second lab of this workshop. In lab 3, we will take a look at replication between two ZFS Appliances.