EMC VNX Series Hardware Information Manual page 22

System component description
Two SPSs
22 VNX5500 Hardware Information Guide
inside the SPS takes the DC power from the DC battery pack and then converts it to AC
power. This AC power then goes from the SPS AC power outlet to the Block and File
(Unified) VNX5500 platform SP
Note: Two SPSs provide higher availability and allow write caching, which prevents data
loss during a power failure, to continue.
IMPORTANT
A faulted or not fully charged SPS disables the write caching.
If AC power fails, the SPS provides backup power until the SP has flushed its write cache
data to the DAE disks. The SP then shuts off SPS power. If the cache flush has not
completed within 90 seconds—more than enough time to flush a full cache—or if the SP
has failed, then the SPS shuts down to prevent a deep discharge. If no AC input power is
available and the SPS is shut down, all the status lights will be off.
The output voltage, when the SPS is in the On-Line state, is a straight pass-through of the
AC-line from inlet to outlets. When in the On-Battery state, the output voltage shall be at
an AC level within the specified limits (see the SPS battery LED in
When power returns, the SPS starts recharging the DC battery pack. It might reach a state
of full charge relatively quickly. If power remains off for a long period—days or weeks—the
DC battery might require more time to charge fully.
write cache unless it detects at least one fully charged SPS.
Battery lifetime depends on the number of discharge cycles and the depth of discharge. In
a typical environment, a battery pack can last 3 to 5 years. The DC battery pack lifetime is
shorter in locations that have frequent AC outages.
Looking from left to right,
SPSs (B and A, respectively).
An additional SPS can be added for redundancy. When only one SPS is used, the AC
power out connectors for the SPS supply AC power to both SP A and SP B.
It is important to cable each SPS so that it connects completely to either the A side or the
B side. For example, if you are looking at the SPSs from the rear, they should be
configured as:
SPS A (rear, right side)—Power-out and sense (management) cables connected to the
◆
SP A power supply.
SPS B (rear, left side)—Power-out and sense (management) cables connected to the
◆
SP B power supply.
1. After a full power outage, an SPS typically requires 45 minutes or a maximum of 75 minutes to
charge. To charge the SPS after being off-line usually requires at least 2 hours.
(Figure 11 on page
1
Figure 11 on page 23 shows an example of the rear view of two
23).
Table 9 on page
The storage processor will not use the
24).