•
The smaller the bandwidth on the WAN, the longer it takes a mirror to synchronize.
•
If the bandwidth does not exceed the average rate, you might not be able to synchronize the data
at all. For example, if the system writes at 1 Mb/s, it needs 2 Mb/s of bandwidth available.
•
If the mirroring is lagging far behind during production hours, suspend the mirror. During off-
peak hours, resume the mirror.
•
If you need to keep the Synchronous Mirroring on at all times, keep the mirror physically as close
as possible to the production site.
•
To determine the average write rate, you should use the available system utilities and should take
measurements during peak times.
•
If you anticipate adding any applications, determine the bandwidth needs for any future
applications.
•
Acceptable lag times vary depending on the environment and should be determined on an
individual basis.
Line capacities
Line type
Capacity in Mb/s
Speed in MB/s
T-1
1.544
0.193
T-3
43.232
5.404
OC-3
155.6352
19.454
OC-12
622.5408
77.8176
OC-48
2490.1632
311.27
OC-192
9960.6528
1245.085
The following table shows average write operations in Mb/s with corresponding line capacity
calculations. When the line capacity calculation is below 50 percent, the result is an adequate
response-time performance and a limited need for delta logging (when the mirror lags behind the
data). When the line capacity calculation is above 50 percent, the mirror can never catch up. Any
transfers above 50 percent will start to lag.
Average write time
in Mb/s
T-1
T-3
OC-3
OC-12
OC-18
OC-192
0.01
5.2%
0.2%
0.1%
0.0%
0.0%
0.0%
0.1
51.8%
1.9%
0.5%
0.1%
0.0%
0.0%
1
518.1%
18.5%
5.1%
1.3%
0.3%
0.1%
10
5181.3%
185.3%
51.4%
12.9%
3.2%
0.8%
Hardware installation for Synchronous Mirroring and Asynchronous Mirroring | 129
Summary of Contents for StorNext QD7000
Page 1: ...Hardware Cabling Guide StorNext QD7000 Firmware 8 40 xx xx 6 68683 01 Rev A...
Page 7: ...Preface Hardware Cabling Guide vii...
Page 10: ...E Series Hardware Cabling Guide December 2017 215 11792_B0 doccomments netapp com...
Page 11: ......
Page 90: ...One E5660 controller drive tray and one DE6600 drive tray Drive shelf or drive tray cabling 81...
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