Operating a non-volatile memory charger

• US 7,782,020 B1
• Filed: 01/14/2005
• Issued: 08/24/2010
• Est. Priority Date: 01/14/2005
• Status: Active Grant

• Current Assignee: Network Appliance Incorporated (NetApp, Inc.)
• Original Assignee: Network Appliance Incorporated (NetApp, Inc.)
• Inventors: Gumtow, Eric
• Primary Examiner(s): Vu; Bao Q
• Assistant Examiner(s): Tran; Nguyen
• Application Number:
  US11/035,638
• Time in Patent Office: 2,048 Days
• Field of Search: 320/149, 320/134, 320/163, 320/48, 320/43, 320/162, 320/132, 320/137, 711/216, 711/322, 711/300, 711/24, 711/22, 713/300, 365/52
• US Class Current: 320/149
• CPC Class Codes: G11C 5/141 Battery and back-up supplies
• CPC Class Codes: H02J 7/007182 in response to battery voltage

Abstract

Provided is a method and system for operating a non-volatile memory charger. Specifically, during the operation of a storage system, the non-volatile memory of the storage system can temporarily store data. The temporarily stored data is flushed to disks of the storage system during the normal operation of the storage system. However, if the storage system is inoperable, then the temporarily stored data is maintained for a time period by a rechargeable battery of the non-volatile memory. The rechargeable battery prevents data loss when the temporarily stored data cannot be flushed to the disks of the storage system. The rechargeable battery maintains sufficient voltage levels to continue to temporarily store data by the operation of a charger connected to the rechargeable battery. A charger policy operated by an operating system of the storage system enables and disables the charging of the rechargeable battery.

Claims

1. A method comprising:

operating, by a storage system comprising an operating system, a non-volatile memory to temporarily store data, the storage system providing a client with access to data stored in a set of mass storage devices over a network, the non-volatile memory including a battery coupled to a charger, and a memory which is made non-volatile by the battery, wherein the storage system, through the operating system, analyzes a voltage level of the charger, and issue a command to operate the charger;

detecting a voltage level of the battery to issue a command to turn on a charger that is coupled to the battery;

issuing a command, by the storage system through the operating system, to turn the charger on to maintain a charge of the battery;

determining a voltage level of the charger is greater than a threshold;

issuing a command, by the storage system through the operating system, to turn the charger off in response to determining the voltage level of the charger is greater than the threshold.

2. A method as recited in claim 1, further comprising using at least three states to operate the charger.

3. A method as recited in claim 2, wherein the at least three states comprise a charger on state, a charger off state, and a normal operation state of the storage system.

4. A method as recited in claim 3, wherein the at least three states further comprise a boot state of the storage system.

5. A method as recited in claim 2, further comprising:

detecting a voltage level of the battery,

wherein at least one of the states is responsive to the voltage level of the battery and at least one of the states is responsive to the voltage level of the charger.

6. A method as recited in claim 1, further comprising:

generating a notification to indicate that the battery is being charged.

7. A method as recited in claim 1, further comprising:

generating a notification to indicate that the battery needs replacement.

8. A method as recited in claim 1, wherein operating a non-volatile memory in a storage system to temporarily store data comprises using the non-volatile memory to temporarily store data between consistency points of the storage system, each said consistency point being characterized by storing of data from temporary storage to the set of mass storage devices.

9. A method as recited in claim 1, wherein issuing the command to turn the charger on to maintain a charge of the battery comprises preventing the storage system from transitioning to a normal operation state when the battery does not have at least a predetermined voltage level.

10. A method as recited in claim 1, wherein issuing the command to turn the charger on to maintain a charge of the battery comprises:

providing a minimum voltage level from the battery to store data and meta-data in the non-volatile memory for at least three days.

11. A method comprising:

operating, by a storage system comprising an operating system, a non-volatile memory to temporarily store data, the storage system providing a client with access to data stored in a set of mass storage devices over a network, the non-volatile memory including a battery coupled to a charger, and a memory which is made non-volatile by the battery, wherein operating the non-volatile memory includes using the non-volatile memory to temporarily store data between consistency points of the storage system, each said consistency point being characterized by storing of data from temporary storage to a set of mass storage devices, wherein the storage system, through the operating system, analyzes a voltage level of the charger, and issues commands to operate the charger;

using, by the storage system, at least three states to operate the charger, the at least three states including a charger on state and a charger off state, wherein at least one of the states is responsive to the voltage level of the battery and at least one of the states is responsive to the voltage level of the charger;

detecting the voltage level of the battery to trigger a transition to the charger on state; and

issuing a command, by the storage system through the operating system, to turn the charger on to maintain a charge of the battery;

detecting the voltage level of the charger is greater than a threshold;

wherein the storage system through the operating system issues a command to transition to the charger off state in response to detecting the voltage level of the charger is greater than the threshold.

12. A method as recited in claim 11, wherein the at least three states comprise a charger on state, a charger off state, and a normal operation state of the storage system.

13. A method as recited in claim 12, wherein the at least three states further comprise a boot state of the storage system.

14. A method as recited in claim 11, further comprising:

generating a notification to indicate that the battery is being charged.

15. A method as recited in claim 11, further comprising:

generating a notification to indicate that the battery needs replacement.

16. A method as recited in claim 11, wherein issuing the command by the operating system to turn the charger on comprises:

providing a minimum voltage level from the battery to store data and meta-data in the non-volatile memory for at least three days.

17. A method as recited in claim 11, wherein issuing the command by the operating system to turn the charger on comprises preventing the storage system from transitioning to a normal operation state when the battery does not have at least a predetermined voltage level.