Many of us always wanted to know what is the file size we would be transfering while we intitate a snapmirror. I have made an real time example here hope it helps

Vol1 is the volume we use for transfering( i have kept the same name at both destination as source for eazy understanding)

sourcefiler> snap list vol1
Volume vol1
working…

%/used %/total date name
———- ———- ———— ——–
2% ( 2%) 1% ( 1%) Oct 23 04:15 destinationfiler(0123456789)_vol1.745 (snapmirror)
5% ( 4%) 2% ( 1%) Oct 22 23:01 hourly.0
9% ( 4%) 3% ( 1%) Oct 21 23:01 hourly.1
12% ( 4%) 4% ( 1%) Oct 20 23:01 hourly.2
18% ( 7%) 6% ( 2%) Oct 19 23:04 hourly.3
21% ( 5%) 7% ( 1%) Oct 18 23:01 hourly.4
25% ( 6%) 9% ( 2%) Oct 17 23:02 hourly.5
28% ( 5%) 11% ( 1%) Oct 16 23:01 hourly.6

In the above we check snap list currently for the volume at the source ( it will list the base snap shot for the source)

destinationfiler*> snap list vol1
Volume vol1
working…

%/used %/total date name
———- ———- ———— ——–
0% ( 0%) 0% ( 0%) Oct 23 04:15 destinationfiler(0123456789)_vol1.745
4% ( 4%) 1% ( 1%) Oct 22 23:01 hourly.0
8% ( 4%) 2% ( 1%) Oct 22 04:15 destinationfiler(0123456789)_vol1.744
8% ( 1%) 2% ( 0%) Oct 21 23:01 hourly.1
11% ( 4%) 3% ( 1%) Oct 20 23:01 hourly.2
17% ( 7%) 6% ( 2%) Oct 19 23:04 hourly.3
20% ( 5%) 7% ( 1%) Oct 18 23:01 hourly.4
25% ( 6%) 9% ( 2%) Oct 17 23:02 hourly.5
27% ( 5%) 10% ( 1%) Oct 16 23:01 hourly.6

Here we check the snapshot which was used last for the snapmirror.

sourcefiler*> snapmirror destinations -s
Path Snapshot Destination

vol1 destinationfiler(0123456789)_vol1.745 destinationfiler:vol1 ( this command tells which was the snapshot used for the snapmirror) in this case its 745

destinationfiler*> snapmirror update vol1
Transfer started.
Monitor progress with ‘snapmirror status’ or the snapmirror log. ( we started a snapmirror update for vol1)

sourcefiler*> snap list vol1 ( once the snapmirror is intiated we see a new snapshot is created which is 746 in our case)
Volume vol1
working…

%/used %/total date name
———- ———- ———— ——–
0% ( 0%) 0% ( 0%) Oct 23 16:46 destinationfiler(0123456789)_vol1.746 (busy,snapmirror)
2% ( 2%) 1% ( 1%) Oct 23 04:15 destinationfiler(0123456789)_vol1.745 (busy,snapmirror)
5% ( 4%) 2% ( 1%) Oct 22 23:01 hourly.0
9% ( 4%) 3% ( 1%) Oct 21 23:01 hourly.1
12% ( 4%) 4% ( 1%) Oct 20 23:01 hourly.2
18% ( 7%) 6% ( 2%) Oct 19 23:04 hourly.3
21% ( 5%) 7% ( 1%) Oct 18 23:01 hourly.4
25% ( 6%) 9% ( 2%) Oct 17 23:02 hourly.5
28% ( 5%) 11% ( 1%) Oct 16 23:01 hourly.6

destinationfiler*> snap list vol1 ( on the destination side we see that 744 is deleted and currently it reference to 745 only)
Volume vol1
working…

%/used %/total date name
———- ———- ———— ——–
0% ( 0%) 0% ( 0%) Oct 23 04:15 destinationfiler(0123456789)_vol1.745
4% ( 4%) 1% ( 1%) Oct 22 23:01 hourly.0
4% ( 1%) 1% ( 0%) Oct 21 23:01 hourly.1
7% ( 4%) 2% ( 1%) Oct 20 23:01 hourly.2
14% ( 7%) 4% ( 2%) Oct 19 23:04 hourly.3
17% ( 5%) 6% ( 1%) Oct 18 23:01 hourly.4
22% ( 6%) 8% ( 2%) Oct 17 23:02 hourly.5
25% ( 5%) 9% ( 1%) Oct 16 23:01 hourly.6

( we do snap delta to check the difference between the snapshots which are currently used in our case its 745 and 746) which shows as 25268240 KB as below)

sourcefiler*> snap delta -V vol1 destinationfiler(0123456789)_vol1.745 destinationfiler(0123456789)_vol1.746

Volume vol1
working…

From Snapshot To KB changed Time Rate (KB/hour)
————— ——————– ———– ———— —————
destinationfiler(0123456789)_vol1.745 destinationfiler(0123456789)_vol1.746 25268240 0d 12:31 2016440.503

this is the size we would be transferring during this snapmirror update process.

destinationfiler*> snapmirror status
Snapmirror is on.
Source Destination State Lag Status
sourcefiler-my_vif-103:vol1 destinationfiler:vol1 Snapmirrored 00:46:56 Idle
sourcefiler-my_vif-103:vol1 destinationfiler:vol1 Snapmirrored 12:34:40 Transferring (9505 MB done)

we can verify after the snapmirror is done by using snapmirror status -l command at the destination.

destinationfiler*> snapmirror status -l vol1
Snapmirror is on.

Source: sourcefiler-my_vif-13:vol1
Destination: destinationfiler:vol1
Status: Idle
Progress: -
State: Snapmirrored
Lag: 00:08:53
Mirror Timestamp: Tue Oct 23 16:46:55 IST 2012
Base Snapshot: destinationfiler(0123456789)_vol1.746
Current Transfer Type: -
Current Transfer Error: -
Contents: Replica
Last Transfer Type: Update
Last Transfer Size: 25268248 KB ( this is one we got using snapdelta command as described earlier)( There is 8kb difference which im not sure of why)
Last Transfer Duration: 00:07:49
Last Transfer From: sourcefiler-my_vif-13:vol1