EMC VMAX 200K - Page 45

Vault to flash
VMAX3 arrays initiate a vault operation if the system is powered down, transitions
offline, or if environmental conditions, such as the loss of a data center due to an air
conditioning failure occur.
Each array comes with Standby Power Supply (SPS) modules. If you lose power, the
array uses the SPS power to write the system mirrored cache onto flash storage.
Vaulted images are fully redundant; the contents of the system mirrored cache are
saved twice to independent flash storage.
The vault operation
When a vault operation is initiated:
l
During the save part of the vault operation, the VMAX3 array stops all I/O. When
the system mirrored cache reaches a consistent state, directors write the
contents to the vault devices, saving two copies of the data. The array then
completes the power down, or, if power down is not required, remains in the
offline state.
l
During the restore part of the operation, the array startup program initializes the
hardware and the environmental system, and restores the system mirrored cache
contents from the saved data (while checking data integrity).
The system resumes normal operation when the SPSes are sufficiently recharged to
support another vault. If any condition is not safe, the system does not resume
operation and notifies Customer Support for diagnosis and repair. This allows
Customer Support to communicate with the array and restore normal system
operations.
Vault configuration considerations
The following configuration considerations apply:
l
To support vault to flash, the VMAX3 arrays require the following number of flash
I/O modules:
n
VMAX 100K two to four per engine
n
VMAX 200K and 400K two to eight per engine
l
The size of the flash module is determined by the amount system cache and
metadata required for the configuration. For the number of supported Flash I/O
module, refer to Table 5 on page 24.
l
The vault space is for internal use only and cannot be used for any other purpose
when the system is online.
l
The total capacity of all vault flash partitions will be sufficient to keep two logical
copies of the persistent portion of the system mirrored cache.
VMAX3 with HYPERMAX OS
Data protection and integrity 45