■
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 193)
.
The following table shows the required capacity for the SDV and the SDPV (guidelines).
Table 73
Required Capacity of SDV/SDPV (Guideline)
Volume
Required capacity (formula)
SDV (*1)
(24 [MB] + NAS user volume capacity
´
0.1 [%])
´
the number of generations
SDPV (SDP)
The update amount for the time interval to acquire snapshots
´
the number of
generations
*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
Snapshot destination
RAID group
NAS user volume
File
File
Expansion area
Directory
: Snapshot
ETERNUS DX
Snap Data Pool (SDP)
Supply
Acquire
Perform differential copy
for each volume when
snapshot is acquired.
●
Required SDP (SDPV) Capacity
An SDP is shared between the Snapshot and the Advanced Copy (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 () in the NAS environment
•
The total data that is saved by Advanced Copy operations (SnapOPC/) in the SAN environment
4. NAS Functions
Snapshot
193
Design Guide
Summary of Contents for ETERNUS DX S5 Series
Page 335: ......
