TECHNIQUES FOR MULTIPLE DIRECTORS CONCURRENTLY SERVICING I/Os DIRECTED TO SAME PHYSICAL STORAGE DEVICES

Patent metadata

Field	Value
Publication number	US-2020034059-A1
Application number	US-201816048637-A
Country	US
Kind code	A1
Filing date	Jul 30, 2018
Priority date	Jul 30, 2018
Publication date	Jan 30, 2020
Grant date	—

Abstract

Techniques for performing configuration may include: determining an initial distribution of logical devices among disk adapters, wherein the initial distribution assigns each logical device a designated disk adapter as a primary active disk adapter servicing I/Os directed to the logical device, wherein the logical devices have storage provisioned from a RAID group including physical storage devices, wherein the disk adapters concurrently issue I/Os to each of the physical storage devices; detecting a configuration change; and responsive to detecting a configuration change, performing first processing. The first processing may include determining, in accordance with the configuration change, a redistribution of the logical devices among the disk adapters; and draining pending I/Os. The configuration change may include adding or removing a logical device provisioned from the RAID group. Performing a first operation on a storage device of the RAID group may include synchronous draining of I/Os of the storage device.

First claim

What is claimed is:

1 . A method of performing configuration comprising:
determining an initial distribution of a plurality of logical devices among a plurality of disk adapters, wherein the initial distribution assigns each of the plurality of logical devices a designated one of the plurality of disk adapters as a primary active disk adapter servicing I/Os directed to said each logical device, wherein the plurality of logical devices have storage provisioned from a RAID group comprising a plurality of physical storage devices, wherein the plurality of disk adapters concurrently issue I/Os to each of the plurality of physical storage devices; detecting a configuration change; and responsive to detecting a configuration change, performing first processing comprising:
determining, in accordance with the configuration change, a redistribution of the plurality of logical devices among the plurality of disk adapters, wherein the redistribution assigns each of the plurality of logical devices a designated one of the plurality of disk adapters as a primary active disk adapter servicing I/Os directed to said each logical device.

2 . The method of claim 1 , wherein the configuration change includes adding new logical device having its storage provisioned from the plurality of physical storage devices of the RAID group, and wherein the redistribution includes assigning a designated one of the plurality of disk adapters as a primary active disk adapter servicing I/Os directed to the new logical device.

3 . The method of claim 1 , wherein the configuration change includes deleting one of the plurality of logical devices having its storage provisioned from the plurality of physical storage devices of the RAID group, and wherein the redistribution includes removing a current assignment of a designated one of the plurality of disk adapters as a primary active disk adapter servicing I/Os directed to said one logical device.

4 . The method of claim 1 , wherein each of the plurality of logical devices has its physical storage provisioned from each of the plurality of physical storage devices of the RAID group.

5 . The method of claim 1 , wherein the initial distribution and the redistribution are performed using a distribution technique that partitions that partitions the plurality of logical devices among the plurality of disk adapters in accordance with one or more balancing criteria.

6 . The method of claim 5 , wherein the one or more balancing criteria include evenly distributing the plurality of logical devices among the plurality of disk adapters.

7 . The method of claim 5 , wherein the plurality of logical devices includes a first portion having a first compression rate or ratio and a second portion have a second compression rate or ratio and the one or more balancing criteria include evenly distributing each of the first portion and the second portion among the plurality of disk adapters.

8 . The method of claim 5 , wherein the plurality of logical devices includes a first portion having compression enabled and a second portion having compression disabled and the one or more balancing criteria include evenly distributing each of the first portion and the second portion among the plurality of disk adapters.

9 . The method of claim 5 , wherein the plurality of logical devices includes a first portion having a first device type and a second portion having a second device type and the one or more balancing criteria include evenly distributing each of the first portion and the second portion among the plurality of disk adapters.

10 . The method of claim 5 , wherein the plurality of logical devices includes a first portion having a first property or attribute and a second portion having a second property or attribute and the one or more balancing criteria include evenly distributing each of the first portion and the second portion among the plurality of disk adapters.

11 . The method of claim 1 , wherein a first of the plurality of logical devices is assigned a first of the plurality of disk adapters as the designated one of the plurality of disk adapters that is the primary active disk adapter servicing I/Os directed to said first logical device, and wherein the first processing includes:
assigning a second of the plurality of disk adapters as the designated one of the plurality of disk adapters that is the primary active disk adapter servicing I/Os directed to said first logical device, wherein, after assigning the second disk adapter, the second disk adapter rather than the first disk adapter services I/Os directed to the first logical device.

12 . The method of claim 11 , wherein the first processing includes:
draining pending I/Os directed to the first logical device, wherein the pending I/Os are issued and managed by the first disk adapter; and receiving one or more additional I/Os directed to the first logical device, wherein the one or more additional I/Os are issued and managed by the second disk adapter.

13 . The method of claim 12 , wherein during said draining, no new I/O operations directed to the first logical device are sent to the first disk adapter for servicing and all subsequently received I/Os directed to the first logical device are sent to the second disk adapter.

14 . The method of claim 13 , wherein at least a first of the pending I/Os managed by the first disk adapter and a second of the one or more additional I/Os are concurrent whereby the first disk adapter and the second disk adapter are concurrently accessing at least one of the plurality of physical storage devices of the RAID group to process the first I/O and the second I/O.

15 . The method of claim 1 , further comprising:
performing a first operation on a first of the physical storage devices of the RAID group requiring synchronous draining of I/Os directed to the first physical storage device.

16 . The method of claim 15 , wherein said synchronous draining includes draining pending I/Os from each of the plurality of directors directed to the first physical storage device.

17 . A system comprising:
a processor; and a memory comprising code stored thereon that, when executed, performs a method of performing configuration comprising:
determining an initial distribution of a plurality of logical devices among a plurality of disk adapters, wherein the initial distribution assigns each of the plurality of logical devices a designated one of the plurality of disk adapters as a primary active disk adapter servicing I/Os directed to said each logical device, wherein the plurality of logical devices have storage provisioned from a RAID group comprising a plurality of physical storage devices, wherein the plurality of disk adapters concurrently issue I/Os to each of the plurality of physical storage devices;
detecting a configuration change; and
responsive to detecting a configuration change, performing first processing comprising:
determining, in accordance with the configuration change, a redistribution of the plurality of logical devices among the plurality of disk adapters, wherein the redistribution assigns each of the plurality of logical devices a designated one of the plurality of disk adapters as a primary active disk adapter servicing I/Os directed to said each logical device.

18 . A computer readable medium comprising code stored thereon that, when executed, performs method of performing configuration comprising:
determining an initial distribution of a plurality of logical devices among a plurality of disk adapters, wherein the initial distribut

Assignees

• Emc Ip Holding Co Llc

Inventors

• Yin Peng
• Gao Kunxiu
• Wang Jiahui
• Pai Seema G
• Li Ningdong
• Wang Daohong
• Ives Stephen Richard
• Lang Li

Classifications

• G06F3/0619

  in relation to data integrity, e.g. data losses, bit errors · CPC title

• G06F3/0689 Primary

  Disk arrays, e.g. RAID, JBOD · CPC title

• G06F3/061

  Improving I/O performance · CPC title

• G06F3/067

  Distributed or networked storage systems, e.g. storage area networks [SAN], network attached storage [NAS] · CPC title

• G06F3/065

  Replication mechanisms · CPC title