vsp mainframe dynamic tiering performance considerations

VSP MAINFRAME DYNAMIC TIERING PERFORMANCE CONSIDERATIONS STEVE RICE, MASTER PERFORMANCE CONSULTANT, MAINFRAME, HITACHI DATA SYSTEMS

SEPTEMBER 12, 2012

WEBTECH EDUCATIONAL SERIES

VSP Mainframe Dynamic Tiering Performance Considerations

A key reason for using dynamic tiering for mainframe storage is

performance. This session will focus on dynamic tiering in mainframe

environments and how to configure and control tiering. The session

ends with a detailed discussion of performance considerations when

using Hitachi Dynamic Tiering.

By attending this webcast, you will

• Understand Hitachi Dynamic Tiering and the options for configuring

and controlling tiering

• Understand the performance considerations and the type of

performance improvements you might experience when you

implement Hitachi Dynamic Tiering

UPCOMING WEBTECHS

Mainframe Series

Mainframe Replication, Sept 19, 9 a.m. PT, 12 p.m. ET

Why Networked FICON Storage Is Better than Direct-attached

Storage, Oct 3, 9 a.m. PT, 12 p.m. ET

Other

Storage Analytics, Sept 20, 9 a.m. PT, 12 p.m. ET

Maximize Availability and Uptime by Clustering your Physical

Datacenters within Metro Distances, Oct 24, 9 a.m. PT, 12 p.m. ET

Check www.hds.com/webtech for

Links to the recording, the presentation and Q&A (available next week)

Schedule and registration for upcoming WebTech sessions

AGENDA

Brief description of tiering

‒ MK-90RD7021 Hitachi Virtual Storage Platform Provisioning Guide for Mainframe

Review RAID terminology

Hitachi Dynamic Provisioning (HDP) terminology and methodology

Discuss Hitachi Dynamic Tiering (HDT) dynamic parameter

Experiments 1 and 2

First steps with HDT and hierarchical storage management

LET TIERING LEARN YOUR WORKLOAD

HDD 3

Continues

HDD 2

Continues

HDD 1

Continues

HDD 0

Continues

RAID TERMINOLOGY: RAID 5 – 3D + 1P LDEV

Parity

Next

8

Tracks

Next

8

Tracks

Track

0-7

Next

8

Tracks

Parity

Next

8

Tracks

Track

8-15

Next

8

Tracks

Next

8

Tracks

Parity

Track

16-23

Next

8

Tracks

Next

8

Tracks

Next

8

Tracks

Parity

RAID Chunk 0

of RAID Stripe 0

RAID Chunk 1

of RAID Stripe 0

RAID Chunk 2

of RAID Stripe 0

RAID Chunk 3

of RAID Stripe 0

RAID Stripe 0

RAID Stripe 1

RAID Stripe 2

RAID Stripe 3

RAID Stripes

Continue

PHYSICAL TO LOGICAL: HDD TO 3390-X HOST-ADDRESSABLE DEVICE LET HDP SHARE THE LOAD

Hard Disk Drive

(HDD)

Parity Group

(PG)

3390-3/9/27/54/A(EAV)

Logical Device

(LDEV)

3390-V

MF-HDP Pool Volume

(Pool-VOL)

3390 –A(EAV)

HDP Volume

(DP-VOL)

3390 –A(EAV) Track Space-Efficient Volume

(TSE-VOL)

Physical Layer

HDS Storage

Subsystem

Abstraction Layer

Host Abstraction Layer or HCD / IOCDS Addressable

HDP PAGE ALLOCATION: 38MB (672 TRACKS)

1 3 2

5

Pool-VOL2

3390-V

(Parity Group 2)

Pool-VOL3

3390-V

(Parity Group 3)

Host

3 2

DP-VOL 3390-A EAV

R/W

4

4

Pool-VOL4

3390-V

(Parity Group 4)

Pool-VOL1

3390-V

(Parity Group 1)

1 5

HDP Pool 7

HDP wide stripes across parity groups

Current implementation of 3390-A(EAV) can have from 1 to 262,668 cylinders

7.5K RPM

SAS or SATA

62%

10K RPM

SAS

36%

HDT PYRAMID: ENGINEERING RECOMMENDATIONS

HDT pyramid within an HDP pool

SSD

2%


Lo

MULTIPLE TIERS WITHIN A SINGLE HDP POOL

Tier 1 - SSD

Tier 2 – SAS 10K or SAS 15K

Tier 3 – SAS 7.5K or External

A SINGLE HDP POOL

EVERY HDP POOL HAS AT LEAST 1 TIER

DP volumes

live within the

HDP pool

DP volume pages

live within 1 or

more tiers

DEFAULT TIER BUFFER SPACE

SAVE A LITTLE SPACE FOR PAGE RELOCATION

Hard Disk Type Buffer area for

Tier Relocation

Buffer Area for New

Page Assignment

Total

SSD 2% 0% 2%

Non-SSD

- SAS 15K HDD

- SAS 10K HDD

- SAS 7.5K HDD

- External

2% 8% 10%

Tier buffer space set at the HDP pool level

HDT CYCLE

Cycle time set at the HDP pool level

Manual mode

‒ User can start and stop performance monitoring using any interval up to 7 days

Automatic mode

‒ Continuous monitoring followed by relocation cycles

‒ Monitor interval from 30 minutes to 1, 2, 4, 8 or 24 hours (default)


Monitor 1 Calc

1

Relocate

1

Monitor 2 Calc

2

Relocate

2

Monitor 3 Calc

3

Relocate

3

Monitor 4 Calc

4

Relocate

4 TIME

T0 T1 T2 T3 T4

Tier 2

Tier 1

HDT MONITORING MODES


Monitoring modes set at the

HDP pool level

Period

‒ The value used in the calculation cycle is the actual IO load on DP volume page from previous monitoring cycle

Continuous

‒ The value used in the calculation cycle is the weighted average of multiple previous monitoring cycles for DP volume page

‒ Reduces page trashing

‒ May slow migration to upper tiers

0

10

20

30

40

50

60

70

80

90

100

110

120

1,005 1,006 1,007 1,008 1,009 1,010

DP

-Vo

lum

e P

age

IOP

H

Tiering Cycle Number

Period vs. Continuous

Period Mode Continuous Mode

RELATIONSHIP BETWEEN NUMBER OF TIERS AND TIERING POLICY

DP VOLUME TIERING POLICIES

Tiering Number of Tiers in Pool Note

Policy 1 Tier 2 Tier 3 Tiers

All All tiers All tiers All tiers Default value; data is

stored in all tiers.

Level 1 All tiers* Tier 1 Tier 1 Data is always stored in

the highest-speed tier

Level 2 All tiers* All tiers* Tier 1 and

Tier 2

Level 3 All tiers* All tiers* Tier 2

Level 4 All tiers* All tiers* Tier 2 and

Tier 3

Level 5 All tiers* Tier 2 Tier 3 Data is always stored in

the lowest-speed tier

* Data is stored in all tiers as in the case of All specified in the tiering policy

NEW PAGE ASSIGNMENT POLICY

TWO TIER TABLE FROM MANUAL

Tiering Level Policy Description

High The new page is assigned from the higher tier of tiers set in the tiering policy

Middle The new page is assigned from the middle tier of tiers set in the tiering policy

Low The new page is assigned from the lower tier of tiers set in the tiering policy

Tiering Level

Policy

When

Specifying

High

When

Specifying

Middle

When

Specifying

Low

Notes

All From Tier 1 to

2

From Tier 1 to

2

From Tier 2 to

1

In the Low setting, tier 2 is given

priority over tier 1

Level 1 From Tier 1 to

2

From Tier 1 to

2

From Tier 1 to

2

Every assignment sequence is the

same as when All is specified as the

tiering level

Level 2

Level 3

Level 4

From Tier 1 to 2 From Tier 1 to 2 From Tier 2 to 1 Every assignment sequence is the same

as when All is specified as the tiering

level

Level 5 From Tier 2 to

1

From Tier 2 to

1

From Tier 2 to

1

Assignment sequences when

High, Middle, and Low are the same

RELOCATION PRIORITY

Use the relocation priority function to set the selection

priority of a DP-VOL when performing relocation – a

prioritized DP-VOL can be relocated earlier during a

relocation cycle

For most effectiveness, use sparingly

“Level 1”?

‒ (NO)

“Level 5”?

‒ (NO)

“ALL”

‒ (Yes, sparingly)

DP VOLUME RELOCATION PRIORITY

HDT EXAMPLE 1

This quick storyboard shows preliminary results from HDT testing

‒ It attempts to show how HDT learns your workload

Scenario: Customer reluctant to upgrade from 300GB to 600GB HDD

Same capacity of HDD (not Including SSD)

‒ (128) 300GB SAS

‒ (64) 600GB SAS + (8) 400GB SSD

IMPORTANT NOTE: SSD drives are added to the pool after all data sets are created

BASIC CONFIGURATION

Config.

Name

RAID

Type

LCU DP-

VOL

per

Pool

PAIO

Data

set

Base /

Alias

Dev.

Num

.

Desc.

HDT3HF RAID-

6(6D+2P)

00 - 03 256 1024 64/192 70xx (128) 300GB

SAS HDP pool

HDT6HF RAID-

6(6D+2P)

08 – 0B 256 1024 64/192 72xx (64) 600GB

SAS HDP pool

HDT6HF

Run 1

through

Run 4

RAID-

6(6D+2P)

08 – 0B 256 1024 64/192 72xx HDT pool

(8) 400GB

SSD

(64) 600GB

SAS

300GB AND 600GB HDP BASELINES HAVE BEEN RUN (NO SSD DRIVES)

HDP (128)

300GB HDD

HDP (64)

600GB HDD

FIRST RUN: 600GB TIER 2 + SSD TIER 1 – 0 MINUTES – NO LEARNING


HDP (128)

300GB HDD

HDP (64)

600GB HDD

Tiering

(64) 600GB:

No learning,

Same as HDP

SECOND RUN: 600GB TIER 2 + SSD TIER 1 – 30 MINUTES OF REST AFTER RUN 1


HDP (128)

300GB HDD

HDP (64)

600GB HDD

Tiering – Run 1:

No learning,

Same as HDP

Tiering – Run 2:

After 30 minutes

of migration

FOURTH RUN: 600GB TIER 2 + SSD TIER 1 – 30 MINUTES OF REST AFTER RUN 3


HDP (128)

300GB HDD

HDP (64)

600GB HDD

Tiering – Run 1:

No learning,

Same as HDP

Tiering – Run 2:

After 30 minutes

of migration

Tiering – Run 3:

After 30 minutes

of migration

Tiering – Run 4:

After 30 minutes

of migration

SUMMARY EXPERIMENT 1

After HDT had a chance to “learn” the workload, it achieved a better response time and more throughput

Other interesting results

‒ After several cycles, HDT migrated 90% of the active PAIO data sets to tier 1, utilizing ONLY 10% of tier 1 – HDT did NOT migrate 100% of the active data sets In other words, not all of the PAIO data sets deserved to be in

the SSD tier, even though PAIO was the only thing active on the system for several hours

‒ If a customer has a performance issue in an HDT environment, more SSD capacity could be installed, increasing residency of active pages in tier 1

HDT EXAMPLE 2

This quick storyboard is another attempt to show how

HDT learns your workload

Same 600GB tier as previous experiment except at a

steady state of 24K IOPS

‒ (64) 600GB SAS drives + (8) 400GB SSD

IMPORTANT NOTE: SSDs are added to the pool after all

data sets are created.

24K IOP STEADY STATE


FIRST STEPS FOR HDT AND HIERARCHICAL STORAGE MANAGEMENT (HSM)

“Hierarchical storage management (HSM) is a data

storage technique which automatically moves data

between high-cost and low-cost storage media”

–Wikipedia

The following slide is an simple example of introducing

HDT in a mainframe environment that utilizes IBM

DFSMShsm


FIRST STEPS FOR HDT AND HSM

HDP (Pool 1)

Primary Space

Level 0

HDP (Pool 2) HSM ML1 and Low-I/O Density DP Volumes

HDP (Pool 3) HSM ML2 and Very Low-I/O Density DP Volumes

Tier 1 - SSD


Near-Line SAS 7.5K

External Volumes

“Level 1”

Adored

“All”

Loved

“Level 5”

Liked

Unliked

Unloved

“All” with “Relocation

Priority” Most Loved

HDT FINAL EXAM

Question

‒ If you utilize all HDT dynamic tiering policies, how many levels of service can be defined in a 3-level tier?

‒ Hint: I did not talk about all of the possible levels, but you can figure it out

Lo


WITH A 3-LEVEL TIER, 7 LEVELS OF SERVICE

Tier 1 - SSD

Tier 3 – SAS 7.5K or External

A SINGLE HDP POOL

AN EXAMPLE OF UTILIZING DYNAMIC TIERING POLICIES

“Level 1”

“Level 4”

“Level 3”

“Level 2”

“Level 5”

“ALL”

“All” with

“Relocation Priority”

SUMMARY


Brief description of tiering

Discuss HDT dynamic parameters

‒ HDT cycle

‒ HDT tiering policy

‒ All

‒ Level 1

‒ Level 5

‒ HDT default tier buffer space

‒ HDT new page assignment policy

‒ ALL (Low) for 2 tier, ALL (Middle) for 3 tier

Experiments 1 and 2

First steps with HDT

QUESTIONS AND DISCUSSION

UPCOMING WEBTECHS

Mainframe Series

Mainframe Replication, Sept 19, 9 a.m. PT, 12 p.m. ET

Why Networked FICON Storage Is Better than Direct-attached

Storage, Oct 3, 9 a.m. PT, 12 p.m. ET

Other

Storage Analytics, Sept 20, 9 a.m. PT, 12 p.m. ET

Maximize Availability and Uptime by Clustering your Physical

Datacenters within Metro Distances, Oct 24, 9 a.m. PT, 12 p.m. ET

Check www.hds.com/webtech for

Links to the recording, the presentation and Q&A (available next week)

Schedule and registration for upcoming WebTech sessions

THANK YOU

vsp mainframe dynamic tiering performance considerations

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