Method and system for multicasting data to persistent memory

Patent metadata

Field	Value
Publication number	US-10019168-B2
Application number	US-201514788129-A
Country	US
Kind code	B2
Filing date	Jun 30, 2015
Priority date	May 19, 2015
Publication date	Jul 10, 2018
Grant date	Jul 10, 2018

Abstract

In general, the technology relates to a method and system for writing data to persistent storage. More specifically, embodiments of the technology relate to writing data to vaulted memory segments in persistent storage using pre-defined multicast address groups. Further, embodiments of the technology take into account the current state of the persistent storage in order to select the vaulted memory segments in which to store the data.

First claim

What is claimed is:

1. A method for storing data in persistent storage, comprising:
selecting a target storage device (SD), wherein the target SD is one of a plurality of SDs in the persistent storage that is currently available to read therefrom and write thereto;
identifying a slice of the persistent storage in which the target SD resides;
determining a first logical SD index within the slice for the target SD
obtaining a bad SD mapping for the slice, where a bad SD mapping comprises a state of each SD of the plurality of SDs;
selecting, from a set of pre-defined multicast address group identifiers (IDs), a subset of pre-defined multicast address group IDs using the first logical SD index;
selecting, from the subset of pre-defined multicast address group IDs, a pre-defined multicast address group ID using a portion of the bad SD mapping that corresponds to the subset of pre-defined multicast address group IDs;
identifying, using the first logical SD index, a vaulted memory segment ID of at least one vaulted memory segment ID associated with the multicast address group ID;
determining a pre-defined multicast address group based on the vaulted memory segment ID;
identifying a second logical SD index associated with the pre-defined multicast address group;
writing the data to a first vaulted memory segment corresponding to the vaulted memory segment ID, wherein the first vaulted memory segment resides in the target SD; and
writing a copy of the data to a second vaulted memory segment corresponding to the vaulted memory segment ID, wherein the second vaulted memory segment resides in a second SD, wherein the second logical SD index within the slice pertains to the second SD.

2. The method of claim 1 , further comprising:
configuring an Input/Output (IO) fabric with the pre-defined multicast address group prior to determining the pre-defined multicast address group,
wherein writing the data to the first vaulted memory segment in the target SD and the copy of the data to the second vaulted memory segment in the second SD comprises using the IO fabric to issue a first IO transaction to the target SD and issue a second IO transaction to the second SD.

3. The method of claim 2 , wherein the first IO transaction comprises the data and a physical address, wherein the second IO transaction comprises the copy of the data and the physical address, and wherein the physical address is selected from an address range associated with the pre-defined multicast address group.

4. The method of claim 1 ,
wherein the persistent storage comprises a second plurality of SDs, wherein the second plurality of SDs comprises the target SD and the second SD, wherein the plurality of SDs comprises the plurality of SDs.

5. The method of claim 1 , wherein the target SD comprises vaulted memory comprising a plurality of vaulted memory segments, wherein the plurality of vaulted memory segments comprises the first vaulted memory segment.

6. The method of claim 5 ,
wherein the target SD further comprises solid state storage,
wherein the method further comprises: copying the data in the first vaulted memory segment into the solid state storage.

7. A storage appliance, comprising:
a processor and a memory;
persistent storage comprising:
a first storage device (SD) currently available to read therefrom and write thereto, wherein the first SD comprises a first vaulted memory segment and a first solid state storage;
a second SD currently available to read therefrom and write thereto, wherein the second SD comprises a second vaulted memory segment and a second solid state storage; and
an Input/Output (IO) fabric interposed between the processor and the persistent storage;

wherein the storage appliance is programmed to:
identify a slice of the persistent storage in which the first SD and the second SD reside;
determine a first logical SD index within the slice for the first SD;
obtain a bad SD mapping for the slice, wherein a bad SD mapping comprises a state of each SD of the plurality of SDs;
select, from a set of pre-defined multicast address group identifiers (IDs), a subset of pre-defined multicast address group IDs using the first logical SD index;
select, from the subset of pre-defined multicast address group IDs, a pre-defined multicast address group ID using a portion of the bad SD mapping that corresponds to the subset of pre-defined multicast address group IDs;
identify, using the first logical SD index, a vaulted memory segment ID of at least one vaulted memory segment ID associated with the multicast address group ID;
determine a pre-defined multicast address group based on the vaulted memory segment ID;
identify a second logical SD index associated with the pre-defined multicast address group;
write the data to the first vaulted memory segment in the first SD, wherein the first vaulted memory segment corresponds to the vaulted memory segment ID; and
write a copy of the data to the second vaulted memory segment in the second SD, wherein the second vaulted memory segment corresponds to the vaulted memory segment ID, wherein the second logical SD index within the slice pertains to the second SD.

8. The storage appliance of claim 7 , wherein the storage appliance is further programmed to:
configure the IO fabric with the pre-defined multicast address group prior to determining the pre-defined multicast address group,
wherein writing the data to the first vaulted memory segment in the first SD and the copy of the data to the second vaulted memory segment in the second SD comprises using the IO fabric to issue a first IO transaction to the first SD and issue a second IO transaction to the second SD.

9. The storage appliance of claim 8 , wherein the first IO transaction comprises the data and a physical address, wherein the second IO transaction comprises the copy of the data and the physical address, and wherein the physical address is selected from an address range associated with the pre-defined multicast address group.

10. The storage appliance of claim 7 ,
wherein the persistent storage further comprises a plurality of SDs, wherein the plurality of SDs comprises the first SD and the second SD.

11. The storage appliance of claim 7 , wherein the first SD comprises vaulted memory comprising a plurality of vaulted memory segments, wherein the the plurality of vaulted memory segments comprises the first vaulted memory segment.

12. The storage appliance of claim 11 ,
wherein the storage appliance is further programmed to: copy the data in the first vaulted memory segment into the first solid state storage.

13. The storage appliance of claim 7 , wherein the IO fabric is implemented using Peripheral Component Interconnect Express (PCIe).

14. The storage appliance of claim 7 , wherein the first solid state storage and the second solid state storage are NAND flash.

15. A non-transitory computer readable medium (CRM) comprising computer readable program code, which when executed by a computer processor, enables the computer processor to:
select a target storage device (SD), wherein the target SD is one of a plurality of SDs in a persistent storage that is currently available to read therefrom and write thereto;
identify a slice of the persistent storage in which the target SD resides;
determine a first logical SD index within the slice for the target SD;
obtain a bad SD mapping for the slice, wherein a bad SD mapping comprises a state of each SD of the plurality of SDs;
select, from a set of pre-defined multicast address group identifiers (IDs), a subset of pre-defined multicast address group IDs using

Assignees

• Emc Corp
• Emc Ip Holding Co Llc

Inventors

• Shapiro Michael W
• Orel Mikhail

Classifications

• H04L12/18

  for broadcast or conference {, e.g. multicast} · CPC title

• G06F3/0688

  Non-volatile semiconductor memory arrays · CPC title

• G06F13/4022

  using switching circuits, e.g. switching matrix, connection or expansion network (G06F13/4009 takes precedence) · CPC title

• G06F3/065

  Replication mechanisms · CPC title

• G06F3/0614

  Improving the reliability of storage systems · CPC title