IBM TotalStorage NAS Gateway 500, Administrator'S Manual

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Preview Unified State Map
Type or select values in entry fields.
Press Enter AFTER making all desired changes
[Entry Fields]
* Device name [] +
5. Enter the name of the device for which to show unified state map information.
To see a list of devices to select, click on the Device Name option and press
F4 . The resulting output shows the unified state map, as illustrated in “Checking
and unifying state maps” on page 299.
Unifying state maps
The gmd_update_state utility sets state cells in the state map to a specific value or
unifies all of the state maps for the specified GeoMirror device. To recover from site
isolation, you need to shut down one site. Then you can unify all the state maps for
all GeoMirror devices on the active site.
Note: You can set state cells in the state map to a specific value, but you must be
extremely careful if you attempt to modify a state map. A mistake can cause
loss of data or data corruption.
For more information on unifying state maps, refer to the section on
″
Updating a
state map device
″
in the High Availability Cluster Multi-Processing XD (Extended
Distance) V5.1: Planning and Administration Guide for HAGEO Technology
(SA22-7956-00).
Site recovery after catastrophic failure
Remote Mirroring is intended to provide timely access to mission-critical data in the
event of a disaster that destroys or disables an entire site location. Problems can
range from an electrical failure involving the entire site to the entire site being
permanently disabled by fire, flood, or an earthquake. Remote Mirroring enables the
restoration of computing services even if all of the hardware must be replaced. If
you must completely replace the hardware and software at a site, or replace a
destroyed site by locating its components in another geographic area, you need
up-to-date copies of the planning worksheets so you can configure the site
according to its state at the time of the disaster. Since there will probably be a great
deal of data to synchronize, the integration process might take a long time. The
time it takes to synchronize depends on several factors:
v
Amount of data changed since the outage: More data increases the time needed
v
Number of GeoMirror devices involved in the process: More mirrors increase the
time needed
v
Size of the GeoMirror devices: Bigger mirrors increase the time needed
v Network bandwidth available: Lower bandwidth increases the time needed
v
Network traffic: High traffic increases the time needed
Appendix C. Remote Mirroring problem determination
301