Creation of ZFS FS,Cloning and Snapshots !!!

Creation of ZFS is very simple.
zfs create ....

We need to set different property values according to our requirement which are helpful to set some limits to our filesystem.

Examples of some properties are quota,reservation,deduplication and compression.

In this post we are going to discuss, 

1) ZFS creation and few properties.
2) ZFS Clones and Snapshots.

ZFS creation with default mountpoint. Default mountpoint will be same as filesystem name.

root-mysrv1~# zpool list
NAME    SIZE  ALLOC   FREE  CAP  HEALTH  ALTROOT
rpool  9.94G  6.12G  3.81G  61%  ONLINE  -
root-mysrv1~#
root-mysrv1~# zpool create mypl c5d1 c5d2 c5d3
root-mysrv1~#
root-mysrv1~# zpool list
NAME    SIZE  ALLOC   FREE  CAP  HEALTH  ALTROOT
mypl    285M    77K   285M   0%  ONLINE  -
rpool  9.94G  6.12G  3.81G  61%  ONLINE  -
root-mysrv1~#

My pool " mypl " created.

root-mysrv1~#
root-mysrv1~# zfs create mypl/myfs1
root-mysrv1~#
root-mysrv1~#
root-mysrv1~# zfs list mypl
NAME  USED  AVAIL  REFER  MOUNTPOINT
mypl  130K   253M    31K  /mypl
root-mysrv1~#
root-mysrv1~#
root-mysrv1~#
root-mysrv1~# df -kh
Filesystem             size   used  avail capacity  Mounted on
rpool/ROOT/s10s_u11wos_24a
                       9.8G   6.1G   3.7G    63%    /
/devices                 0K     0K     0K     0%    /devices
ctfs                     0K     0K     0K     0%    /system/contract
proc                     0K     0K     0K     0%    /proc
mnttab                   0K     0K     0K     0%    /etc/mnttab
swap                   4.7G   504K   4.7G     1%    /etc/svc/volatile
objfs                    0K     0K     0K     0%    /system/object
sharefs                  0K     0K     0K     0%    /etc/dfs/sharetab
/platform/SUNW,Sun-Fire-T200/lib/libc_psr/libc_psr_hwcap1.so.1
                       9.8G   6.1G   3.7G    63%    /platform/sun4v/lib/libc_psr.so.1
/platform/SUNW,Sun-Fire-T200/lib/sparcv9/libc_psr/libc_psr_hwcap1.so.1
                       9.8G   6.1G   3.7G    63%    /platform/sun4v/lib/sparcv9/libc_psr.so.1
fd                       0K     0K     0K     0%    /dev/fd
swap                   4.7G    32K   4.7G     1%    /tmp
swap                   4.7G    48K   4.7G     1%    /var/run
rpool/export           9.8G    32K   3.7G     1%    /export
rpool/export/home      9.8G    31K   3.7G     1%    /export/home
rpool                  9.8G   106K   3.7G     1%    /rpool
mypl                   253M    31K   253M     1%    /mypl
mypl/myfs1             253M    31K   253M     1%    /mypl/myfs1
root-mysrv1~#
root-mysrv1~# zpool list
NAME    SIZE  ALLOC   FREE  CAP  HEALTH  ALTROOT
mypl    285M   222K   285M   0%  ONLINE  -
rpool  9.94G  6.13G  3.81G  61%  ONLINE  -
root-mysrv1~#
root-mysrv1~#
root-mysrv1~# zfs list
NAME                         USED  AVAIL  REFER  MOUNTPOINT
mypl                         130K   253M    32K  /mypl
mypl/myfs1                    31K   253M    31K  /mypl/myfs1
rpool                       6.12G  3.66G   106K  /rpool
rpool/ROOT                  6.12G  3.66G    31K  legacy
rpool/ROOT/s10s_u11wos_24a  6.12G  3.66G  6.12G  /
rpool/export                  63K  3.66G    32K  /export
rpool/export/home             31K  3.66G    31K  /export/home
root-mysrv1~#
root-mysrv1~#

ZFS creation with specific mountpoint for our filesystem.

root-mysrv1~#
root-mysrv1~# zfs create -o mountpoint=/mypl/mysap mypl/sapmnt
root-mysrv1~#
root-mysrv1~# df -kh | grep mypl
mypl                   253M    32K   253M     1%    /mypl
mypl/myfs1             253M    31K   253M     1%    /mypl/myfs1
mypl/sapmnt            253M    31K   253M     1%    /mypl/mysap
root-mysrv1~#
root-mysrv1~#
root-mysrv1~# zfs list |grep mypl
mypl                         176K   253M    32K  /mypl
mypl/myfs1                    31K   253M    31K  /mypl/myfs1
mypl/sapmnt                   31K   253M    31K  /mypl/mysap
root-mysrv1~#

***********************************************************************

Let us discuss some properties,

First of all , we should have clear idea about difference between QUOTA and RESERVATION.

Quota is to set a limit on the amount of space a file system can use.
Reservation is an allocation of space from the pool that is guaranteed to be available to a dateset.

Either we can set property at the time of FS creation or we can set it later....

Now let us create a new FS with some quota.....

root-mysrv1~#
root-mysrv1~# zfs create -o mountpoint=/mypl/myspl -o quota=1m mypl/spl
root-mysrv1~#
root-mysrv1~#
root-mysrv1~# zfs list |grep mypl
mypl                         224K   253M    33K  /mypl
mypl/myfs1                    31K   253M    31K  /mypl/myfs1
mypl/sapmnt                   31K   253M    31K  /mypl/mysap
mypl/spl                      31K   993K    31K  /mypl/myspl
root-mysrv1~#
root-mysrv1~#
root-mysrv1~# df -kh | grep mypl
mypl                   253M    33K   253M     1%    /mypl
mypl/myfs1             253M    31K   253M     1%    /mypl/myfs1
mypl/sapmnt            253M    31K   253M     1%    /mypl/mysap
mypl/spl               1.0M    31K   993K     4%    /mypl/myspl
root-mysrv1~#

To view our property value, or else for all properties values we can give zfs get all fsname.

root-mysrv1~# zfs get quota mypl/spl     
NAME      PROPERTY  VALUE  SOURCE
mypl/spl  quota     1M     local
root-mysrv1~#
root-mysrv1~#
root-mysrv1~# zfs set quota=10m mypl/spl          ---- now we can change the value, if necessary..
root-mysrv1~#
root-mysrv1~#
root-mysrv1~# zfs get quota mypl/spl
NAME      PROPERTY  VALUE  SOURCE
mypl/spl  quota     10M    local
root-mysrv1~#
root-mysrv1~#
root-mysrv1~# df -kh | grep mypl
mypl                   253M    34K   253M     1%    /mypl
mypl/myfs1             253M    31K   253M     1%    /mypl/myfs1
mypl/sapmnt            253M    31K   253M     1%    /mypl/mysap
mypl/spl                10M    31K  10.0M     1%    /mypl/myspl
root-mysrv1~#
root-mysrv1~#
root-mysrv1~# zfs list |grep mypl
mypl                         226K   253M    34K  /mypl
mypl/myfs1                    31K   253M    31K  /mypl/myfs1
mypl/sapmnt                   31K   253M    31K  /mypl/mysap
mypl/spl                      31K  9.97M    31K  /mypl/myspl
root-mysrv1~#

To set quota for an existing filesystem...

root-mysrv1~# zfs set quota=50m mypl/sapmnt
root-mysrv1~#
root-mysrv1~#
root-mysrv1~# zfs list |grep mypl
mypl                         226K   253M    34K  /mypl
mypl/myfs1                    31K   253M    31K  /mypl/myfs1
mypl/sapmnt                   31K  50.0M    31K  /mypl/mysap
mypl/spl                      31K  9.97M    31K  /mypl/myspl
root-mysrv1~#
root-mysrv1~# zpool status mypl
  pool: mypl
 state: ONLINE
 scan: none requested
config:
        NAME        STATE     READ WRITE CKSUM
        mypl        ONLINE       0     0     0
          c5d1      ONLINE       0     0     0
          c5d2      ONLINE       0     0     0
          c5d3      ONLINE       0     0     0
errors: No known data errors
root-mysrv1~#

***********************************************************************

ZFS snapshots : It is very helpful , to revert back wrong situation.

It is always suggestible to take a snapshot of your existing filesystem before performing some activity or applying some modifications to our existing FS.

Main thing with snapshots is, A snapshot does not occupy any space.It just takes a snap of entire filesystem.

It is helpful to revert when something goes wrong because of an activity.

root-mysrv1~#
root-mysrv1~# df -kh | grep mypl
mypl                   253M    34K   253M     1%    /mypl
mypl/myfs1             253M    31K   253M     1%    /mypl/myfs1
mypl/sapmnt             50M    31K    50M     1%    /mypl/mysap
mypl/spl                10M    31K  10.0M     1%    /mypl/myspl
root-mysrv1~#
root-mysrv1~#
root-mysrv1~#
root-mysrv1~# zfs list |grep mypl
mypl                         228K   253M    34K  /mypl
mypl/myfs1                    31K   253M    31K  /mypl/myfs1
mypl/sapmnt                   31K  50.0M    31K  /mypl/mysap
mypl/spl                      31K  9.97M    31K  /mypl/myspl
root-mysrv1~#
root-mysrv1~#

Here I am creating a snapshot for my FS at initial state.

root-mysrv1~# zfs snapshot mypl/spl@may2014
root-mysrv1~#
root-mysrv1~#
root-mysrv1~# zfs list | grep mypl
mypl                         229K   253M    34K  /mypl
mypl/myfs1                    31K   253M    31K  /mypl/myfs1
mypl/sapmnt                   31K  50.0M    31K  /mypl/mysap
mypl/spl                      31K  9.97M    31K  /mypl/myspl
mypl/spl@may2014                0      -    31K  -
root-mysrv1~#
root-mysrv1~#
root-mysrv1~# cd /
root-mysrv1~#
root-mysrv1~# du -sh *
   0K   bin
 295K   boot
 500M   dev
 176K   devices
  49M   etc
   3K   export
   0K   home
  61M   kernel
  36M   lib
   1K   mnt
   6K   mypl
   0K   net
 138M   opt
   1K   pl1
 320M   platform
 824M   proc
  78K   rpool
 1.6M   sbin
 8.6M   system
   6K   test
  80K   tmp
^C
root-mysrv1~#
root-mysrv1~#
root-mysrv1~# cd sbin
root-mysrv1~# ls
autopush     ifconfig     metainit     rc2          su           umountall
bootadm      ifparse      metarecover  rc3          su.static    uname
bpgetfile    in.mpathd    metastat     rc5          sulogin      zfs
dhcpagent    init         mount        rc6          swapadd      zonename
dhcpinfo     jsh          mountall     rcS          sync         zpool
dladm        luactivate   netstrategy  route        tnctl
fdisk        lucurr       pfsh         routeadm     tzreload
fiocompress  metadb       rc0          sh           uadmin
hostconfig   metadevadm   rc1          soconfig     umount
root-mysrv1~#

To apply some changes, let us copy some data to our filesystem.

root-mysrv1~# cp -rp /sbin /mypl/myspl
root-mysrv1~#
root-mysrv1~#
root-mysrv1~# cd /mypl/myspl
root-mysrv1~#
root-mysrv1~# ls -rlth
total 5
drwxr-xr-x   2 root     sys           52 Apr  5 08:32 sbin
root-mysrv1~#
root-mysrv1~# df -kh | grep mypl
mypl                   253M    34K   251M     1%    /mypl
mypl/myfs1             253M    31K   251M     1%    /mypl/myfs1
mypl/sapmnt             50M    31K    50M     1%    /mypl/mysap
mypl/spl                10M   1.8M   8.2M    18%    /mypl/myspl
root-mysrv1~#
root-mysrv1~#

Again take a snapshot after copying some files...

root-mysrv1~#
root-mysrv1~# zfs snapshot mypl/spl@may20142nd
root-mysrv1~#
root-mysrv1~#
root-mysrv1~# zfs list |grep mypl
mypl                        2.39M   251M    34K  /mypl
mypl/myfs1                    31K   251M    31K  /mypl/myfs1
mypl/sapmnt                   31K  50.0M    31K  /mypl/mysap
mypl/spl                    1.96M  8.04M  1.94M  /mypl/myspl
mypl/spl@may2014              19K      -    31K  -
mypl/spl@may20142nd             0      -  1.94M  -
root-mysrv1~#

As we can see the initial snap occupied some space, but the second snap is 0K.
Now let us rollback our situation...

root-mysrv1~#
root-mysrv1~# zfs rollback mypl/spl@may2014
cannot rollback to 'mypl/spl@may2014': more recent snapshots exist
use '-r' to force deletion of the following snapshots:
mypl/spl@may20142nd
root-mysrv1~#
root-mysrv1~# zfs rollback -r mypl/spl@may2014
root-mysrv1~#
root-mysrv1~#
root-mysrv1~# zfs list |grep mypl
mypl                         268K   253M    34K  /mypl
mypl/myfs1                    31K   253M    31K  /mypl/myfs1
mypl/sapmnt                   31K  50.0M    31K  /mypl/mysap
mypl/spl                      32K  9.97M    31K  /mypl/myspl
mypl/spl@may2014               1K      -    31K  -
root-mysrv1~#
root-mysrv1~#
root-mysrv1~# df -kh | grep mypl
mypl                   253M    34K   253M     1%    /mypl
mypl/myfs1             253M    31K   253M     1%    /mypl/myfs1
mypl/sapmnt             50M    31K    50M     1%    /mypl/mysap
mypl/spl                10M    31K  10.0M     1%    /mypl/myspl
root-mysrv1~#
root-mysrv1~#
root-mysrv1~# cd /mypl/myspl
root-mysrv1~#
root-mysrv1~# ls
root-mysrv1~#        ------ Previously there is no data in my filesystem and so my FS is rolled back.

To destroy a snapshot ,

root-mysrv1~#
root-mysrv1~# zfs list |grep mypl
mypl                         268K   253M    34K  /mypl
mypl/myfs1                    31K   253M    31K  /mypl/myfs1
mypl/sapmnt                   31K  50.0M    31K  /mypl/mysap
mypl/spl                      32K  9.97M    31K  /mypl/myspl
mypl/spl@may2014               1K      -    31K  -
root-mysrv1~#
root-mysrv1~#
root-mysrv1~# zfs destroy mypl/spl@may2014
root-mysrv1~#
root-mysrv1~#
root-mysrv1~# zfs list |grep mypl
mypl                         456K   253M    34K  /mypl
mypl/myfs1                    31K   253M    31K  /mypl/myfs1
mypl/sapmnt                   31K  50.0M    31K  /mypl/mysap
mypl/spl                      31K  9.97M    31K  /mypl/myspl
root-mysrv1~#

ZFS cloning : A clone is a exact copy of our existing filesystem. We can clone a FS from its snapshot only. So whenever we need a clone copy of FS, just we need to take its snap and can create a clone from it.

root-mysrv1~#
root-mysrv1~# zpool list
NAME    SIZE  ALLOC   FREE  CAP  HEALTH  ALTROOT
mypl    285M   344K   285M   0%  ONLINE  -
rpool  9.94G  6.13G  3.81G  61%  ONLINE  -
root-mysrv1~#
root-mysrv1~# zpool list |grep mypl
mypl    285M   344K   285M   0%  ONLINE  -
root-mysrv1~#
root-mysrv1~#
root-mysrv1~# zfs list |grep mypl
mypl                         247K   253M    34K  /mypl
mypl/myfs1                    31K   253M    31K  /mypl/myfs1
mypl/sapmnt                   31K  50.0M    31K  /mypl/mysap
mypl/spl                      31K  9.97M    31K  /mypl/myspl
root-mysrv1~#
root-mysrv1~# zfs clone mypl/spl mypl/spl_very               ---- can clone a FS from its snapshot only.
cannot open 'mypl/spl': operation not applicable to datasets of this type
root-mysrv1~#
root-mysrv1~# zfs snapshot mypl/spl@12345                    ---- creating snapshot.
root-mysrv1~#
root-mysrv1~# zfs list |grep mypl
mypl                         252K   253M    34K  /mypl
mypl/myfs1                    31K   253M    31K  /mypl/myfs1
mypl/sapmnt                   31K  50.0M    31K  /mypl/mysap
mypl/spl                      31K  9.97M    31K  /mypl/myspl
mypl/spl@12345                  0      -    31K  -
root-mysrv1~#
root-mysrv1~# zfs clone mypl/spl@12345 mypl/spl_very    ---- creating clone 
root-mysrv1~#
root-mysrv1~# zfs list |grep mypl
mypl                         274K   253M    34K  /mypl
mypl/myfs1                    31K   253M    31K  /mypl/myfs1
mypl/sapmnt                   31K  50.0M    31K  /mypl/mysap
mypl/spl                      31K  9.97M    31K  /mypl/myspl
mypl/spl@12345                  0      -    31K  -
mypl/spl_very                  1K   253M    31K  /mypl/spl_very
root-mysrv1~#
root-mysrv1~#
root-mysrv1~# zfs clone -o mountpoint=/splclone mypl/spl@12345 mypl/cln1
root-mysrv1~#
root-mysrv1~#
root-mysrv1~# zfs list |grep mypl
mypl                         312K   253M    36K  /mypl
mypl/cln1                      1K   253M    31K  /splclone
mypl/myfs1                    31K   253M    31K  /mypl/myfs1
mypl/sapmnt                   31K  50.0M    31K  /mypl/mysap
mypl/spl                      31K  9.97M    31K  /mypl/myspl
mypl/spl@12345                  0      -    31K  -
mypl/spl_very                  1K   253M    31K  /mypl/spl_very
root-mysrv1~#

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