Figure 95 Snapshot; Table 73 Required Capacity Of Sdv/Sdpv (Guideline) - Fujitsu ETERNUS DX S5 Series Design Manual

4. NAS Functions
Snapshot
■
NAS Snapshot Destination Volumes
To acquire snapshots, prepare snapshot destination volumes (an SDV and an SDPV). For details on volumes,
refer to "■ NAS Snapshot Destination Volumes" (page
The following table shows the required capacity for the SDV and the SDPV (guidelines).
Table 73 Required Capacity of SDV/SDPV (Guideline)
Volume
SDV (*1)
SDPV (SDP)
*1: The physical capacity required for creating an SDV. The logical capacity (capacity seen from the server) is the same as that of the NAS
user volume.
Figure 95 Snapshot
NAS user volume
Directory
●
Required SDP (SDPV) Capacity
An SDP is shared between the Snapshot and the Advanced Copy (SnapOPC/SnapOPC+) in the SAN or NAS
environment. Calculate the required capacity for each respectively.
The total SDPV capacity must be larger than the total amount of data that is saved to the SDV. The total
amount of data that is saved to the SDV is the sum of the following data.
• The total data that is saved by the Snapshot function
The total data that is saved by Advanced Copy operations (SnapOPC+) in the NAS environment
•
• The total data that is saved by Advanced Copy operations (SnapOPC/SnapOPC+) in the SAN environment
Required capacity (formula)
(24 [MB] + NAS user volume capacity ´ 0.1 [%]) ´ the number of generations
The update amount for the time interval to acquire snapshots ´ the number of
generations
ETERNUS DX
File
File
Perform differential copy
for each volume when
snapshot is acquired.
193).
Snap Data Pool (SDP)
Expansion area
Supply
Acquire
Snapshot destination
RAID group
193
: Snapshot
Design Guide