Tip for Compute Blade 500 Power Settings. Preface. Contents

Transcription

1 Preface This tip will help you understand the power settings of Compute Blade 500 (CB500) further. Refer to Hitachi Compute Blade 500 Series Product Ordering Guide if you need basic information. Contents Preface How to set the CB500 power settings Power supply module redundancy (N+1 and N+N) Power supply module optimization Power capacity expansion feature Case Study... 6 (1)Premise: Customer s facility... 6 (2)Phenomena... 6 (3)The lowest supply power... 7 (4)Solution... 7

2 1. How to set the CB500 power settings Use CB500 Web console when you want to confirm or modify the power settings. Web console Resources Systems Power Management These 3 settings in the red frame are the power settings for CB500. The following sections tell the meaning of each setting.

3 2. Power supply module redundancy (N+1 and N+N) CB500 has 2 power supply module redundancy modes, which are adaptable to 2 kinds of the customer s power distribution board. If the customer uses a single power distribution board, CB500 should be set to N+1 mode. This mode has 3 active and 1 standby power supply modules. If the customer uses a dual power distribution board, CB500 should be set to N+N mode. This mode has 2 active and 2 standby power supply modules. Single power distribution board Dual power distribution boards N+1 mode (3 active and 1 standby) N+N mode (2 active and 2 standby) What s the difference between N+1 and N+N mode? The active power supply means the user-available power. N+1 mode has 3 active power supplies and its total power is 6,426W. N+N mode has 2 active power supplies and its total power is 4,284W. The module redundancy means the redundancy of power supply modules. Both N+1 and N+N modes have power supply redundancy. Only N+N mode has the distribution board redundancy. N+1 mode N+N mode Active power supply Module redundancy (DC redundancy) 6,426 W (2,142 W x 3 active) Yes 4,284 W (2,142 W x 2 active) Yes Distribution board redundancy (AC redundancy) No Yes

4 3. Power supply module optimization The efficiency of power conversion is high under heavy load. CB500 has a function which turns off excessive power supply modules to increase the efficiency of power conversion. Conversion efficiency Keeping heavy load makes the conversion efficiency high. Power load As an example, in the case the total power consumption of CB500 is 2,000W, if 2 power supply modules runs, the total available power is 4,284W and the loading rate is 48%. If CB500 turns off one of the power supply modules, the total available power falls down to 2,142W and the loading rate rises to 93%. This function provides the high loading rate and the high efficiency of power conversion. ex. CB500 has total 2,000W power load. Each power supply module has the capability of 2,142W. 2,142W x 2 modules = 4,284W 2,000W / 4,284W = 47% loading rate 2,142W x 1 modules = 2,142W 2,000W / 2,142W = 93% loading rate

5 4. Power capacity expansion feature CB500 does not include the power from redundant power supply modules in its total power supply capability. Even if one of the distribution boards fails, the total power supply capability keeps being the same as before. Power capacity expansion feature : Disable Power capacity expansion feature can be enabled only when power supply modules have redundancy. This function utilizes some amount of the power of redundant power supply modules. And each power supply is boosted up from 2,142W to 2,436W. This mode is disabled automatically when the redundancy is lost. Power capacity expansion feature : Enable

6 5. Case Study Problem: Even though power supplies have redundancy some blades were powered off unexpectedly when an electric outage occurred on one of the customer s power distribution boards. Cause: Inadequate power settings caused the problem. (1) Premise: Customer s facility The customer had divided their power distribution board to 2 lines. The power settings of the CB500 should be set as N+N mode, but was set as N+1 mode. And its Power supply module optimization was enabled. An electric power outage occurred on the distribution board #A. (2) Phenomena The details of phenomena are as follows. PS2 has been OFF via the Power supply module optimization feature since May 26. PS1 and PS3 were OFF due to the electric outage on August 2. At the instant PS1 and PS3 went OFF, and only PS0 was ON with 1,285W. The number of shutdown blades depends on the Chassis electric power consumption: Chassis: 1,728W 4 blades should be OFF in order to be less than 1,285W. The management module turned PS2 ON when it detected the loss of N+1 redundancy.

7 (3) The lowest supply power The following matrixes show the lowest supply power with each redundancy mode in the case Power supply module optimization : Enable/Disable and Power capacity expansion feature : Enable/Disable. As the customer used N+1 mode, the lowest supply power was 1,285W. In this customer case, the lowest supply power goes up from 1,285W to 2,436W if the customer changes the redundancy mode from N+1 to N+N. (4) Solution This setting change will solve the problem. The details after the change are as follows. PS2 and PS3 are OFF via the Power supply module optimization feature. If PS1 is OFF due to an electric outage, PS1 goes OFF and only PS0 is ON with 2,436W. As the power consumption of the chassis is around 1,700W, all blades keep running. The management module turns PS2 ON when it detects the loss of N+N redundancy.