Capacity Management for SAN

Capacity Management for SAN Attached Storage

Warning: Low Disk Space

Metron

www.metron-athene.com

Metron-Athene

• Established 1986

• Stable ownership

• Consistent Focus on CM

• Industry Leadership

Athene

Control Center

Capacity Database

Data Source

FrameworkAcquire DB/Application

Virtual Server Custom

z/OS, HP-UX, AIX, Solaris, Linux

Objectives

• Trends in storage technology.

• Define two distinct aspects of storage capacity.

• Examine key areas related to capacity management of SAN attached storage.

• Equate with business value.

• Show how tools like Athene can help you achieve your goals.

• Provide ideas about how to proceed with improving storage capacity management processes in your environment.

Trends

• Solid state devices

• Cloud storage

• Embedded storage (e.g. Exadata, vBlock)

• Big data (e.g. Hadoop)

• Tiered storage

• Primary de-duplication

• FCoE, 16 Gbps Fiber, and 10 Gbps Ethernet

Two Distinct Aspects of Storage Capacity

Disk Space Capacity

Disk Performance Capacity

Bytes

Response, IOPs

Space Capacity – Growth (measureable)

Changing demands for storage – Slope of line

Space Capacity - History

Growth can result in increasing cost and complexity

Space Capacity – Growth and Cost Factors

Growth• Business as usual (Trend)• Acquisitions• New applications and projects

Costs• Equipment, including power• Resource management, including people• Storage use by application (Billable Customers)

Space Capacity – Storage as a Service

How much are customers consuming?

Don’t forget about the IT department and other insiders!

Space Capacity – Tiered Service Model

Define what tiers are (platinum, gold, silver, etc…)

Rates should be adjusted on a frequent basis.

Billing is an effective way to create accountability.

Estimate growth versus storage cost declines.

Space Capacity – Management Support

Effective storage management happens with a bridge to business results, and building that bridge begins with a solid foundation. Show business value to be self evident.

Space Capacity – Business View

With management backing, important processes can be implemented

• Capacity budgeting and inventory management

• Mandatory storage request process

• Storage mapping to determine ownership

• Chargeback of some form• Define executive reporting

requirements

Once the bridge is built reporting information can flow freely

ITBusiness

Space Capacity – Who is Responsible

Managing storage capacity requires work.

Storage administrators typically have limited time and higher priorities in their complex environments.

Space Capacity – Over and Under Provisioning

Administrators may have no choice but to over allocate which results in low utilization.

It is important to define exactly what ‘Utilization’ is for your storage.

Many factors determine what ‘Right Sized’ means for each system. But, running out of space means only one thing to all.

Space Capacity – Doing the Technical Work

After roles and responsibilities are assigned and business requirements are complete, technical solutions can be implemented to optimize storage space management, including databases.

Trending, forecasting, and exceptions.

Space Capacity – Different Viewpoints

Business, Application, Host, Storage Array, Billing Tier

If billing for storage ensure transparency with detail reports

Space Capacity – Virtual Environments and Clusters

Managing storage in clustered and/or virtual environment can be challenging because it is shared among all hosts and virtual machines running on it.

• Manage capacity at a high level

• Account for storage use at a low level, e.g. VM or DB

• If billing be cautious of different tiers being allocated to the same cluster.

• Don’t forget about overhead

Overcommit with thin provisioning

Space Capacity – Storage Virtualization

Pooling physical storage from multiple sources into logical groupings

• Simplifies Administration

• Can be a centralized source for collecting data

• If using as a data source beware of double counting with backend

• Don’t forget about overhead for replication

Wide variety of techniques for virtualizing storage, be aware of the implications for data collection and reporting

Space Capacity – Best Practices

Find dark and hidden storage, where it has been allocated and never used, or plugged into a different box.

Use thin provisioning and de-duplication where possible.

Include data retention policies for storage space management.

Account for overhead from RAID, replication, file systems, etc…

Understand the value of data in deciding where to put it, how to protect it, and how long to keep it.

Space Capacity – Best Practices

Understand the limitations of linear regression when trending and forecasting data. Use statistics like R^2 to confirm.

Be sure to account for all variables when ‘Right Sizing’!

Include directory and file level reporting for file servers if possible.

Performance Capacity – Response Impacts

SAN or storage array performance problems can have serious impacts over a long duration, and be difficult to identify.

Performance Capacity – Metrics

Understand the limitations of certain metrics

• Measured response is the best metric for identifying trouble.

• Host utilization only shows busy time, it doesn’t give capacity for SAN.

• Physical IOPs is an important measure of throughput, all disks have their limitation.

• Queue Length is a good indicator that a limitation has been reached somewhere.

Many times critical host disk metrics are not breached during impactful events.

Are these potential problems having a real impact?

Consider using Statistical Process Control

Performance Capacity – Metric Thresholds

Performance Capacity – Metric Thresholds (Host)

Other times certain metrics like utilization are indicating impactful events, but ample capacity is still available.

Performance Capacity – Metric Thresholds (Host)

Queue lengths from the previous utilization indicate that it may not currently be impacting response, but headroom is unknown.

Performance Capacity – Metric Thresholds (Host)

The high utilization can be seen generating large amounts of I/O in this chart.

Performance Capacity – Architecture (Array)

• Front End Processors

• Shared Cache

• Back End Processors

• Disk Storage

Performance Capacity – Metric Thresholds (Array)

Front end processors are typically the first to bottleneck

Performance Capacity – Metric Thresholds (Array)

Impact of utilization on response for a single processor

Curves based on simple queuing with normal distribution

Performance Capacity – Component Breakdown

Service time versus response time – different metrics

Performance Capacity – Workload Profiles

I/O profile has a big impact on performance. Be sure to include it when comparing applications.

Test with tools like Iometer, IOzone, Bonnie, etc…

Performance Capacity – Best Practices

Performance Capacity – Best Practices

Trending, forecasting, and exceptions with Athene

Performance Capacity – Best Practices

• Choose service levels and establish baselines.

• Use available data sources, vendor utilities, etc…

• Consolidate reporting tools and data. (Athene)

Storage Capacity – Final Thoughts

• Talk with storage team about current state of reporting and fill in the gaps.

• Fabric and network utilization might be in scope.

• Set priorities for where to spend time and effort.

• Simplify where possible.

• Work to establish formal naming conventions where needed.

• Tools - without knowledge, experience, and commitment won’t help.

Capacity Management for SAN Attached Storage

Storage Capacity – Thank you for attending

Dale Feiste

Metron-Athene Inc.

[email protected]