Changing Storage Vendors – What is Important, Part 3

By Randy Kerns, Wednesday, October 19th 2022

Analyst Blogs

This is Part 3 of this blog series. Read Part 2 here

This is the third installment in a series about considerations for IT in changing storage vendors and storage systems.  Changing storage vendors is a decision that is not taken without careful consideration by IT professionals and has significant implications.  This series examines the evaluation of vendor storage solutions as part of the decision to change storage vendors.

Part 1 dealt with reasons for changing storage vendors and Part 2 explained evaluating a storage vendor.  This part will provide insights into how to evaluate storage solutions offered by a vendor when making a decision to change.  Existing available information will be highlighted that is highly valuable in this exercise.

Evaluating a Storage Solution

Different types of data and uses drive a decision to store data on block, file, or object storage.  Block storage systems are normally associated with higher performance requirements and business critical applications than files on NAS (Network Attached Storage) or objects on object storage systems.  The different types of storage and access methods drive different requirements and product characteristics.  Those special characteristics will be examined in upcoming installments.  For considering a change of vendor and storage system, there are common elements in the evaluation of the selection of a storage system.

First, a comment on storage offerings that are “universal” storage, providing block, file, and object or some combination.  Over the many years of vendors providing unique storage solutions, there have been a number of the universal storage offerings.  Some have been successful but most IT organization deploy systems with a single type of storage access.  There are several reasons but the most common is that when storage is being purchased, it is for a specific usage and the funds for the purchase may be directed to only that usage.  A solution that is universal sounds good but is not normally the focus for IT in evaluating and selecting and storage system.  There is also the historical perspective that systems dedicated to specific usages are optimized for that usage, providing advantages.  There will continue to be universal storage solutions and that may have value for IT organizations.  These articles will focus on the independent usages.  Evaluations of combined usages can be an aggregate of the individual evaluations.

Establish Criteria

Making a decision when selecting the storage solution when changing vendors requires establishing what are the important criteria.  The is where the separation between what is important/needed for the organization and what the vendor is promoting occurs.  Evaluator Group maintains a criteria selection list for comparative matrices and for the Evaluator Group opinion ratings called EvaluScale, available on the website .  These are specific to every technology area covered.  They are based on what our clients tell us is important during engagements and are re-evaluated at the end of each year for updating.

Below is an example showing the criteria for SAN high end block storage systems.  The criteria will be different for other technologies.  Note that Evaluator Group will retain comparatives for products that have been withdrawn for a period of time before removal.

Common elements between the different storage technologies that need to be part of the evaluation are included below.

Common Elements in Evaluations

Price and Capacity

As storage solutions have continued to progress in technology and functionality, much of the differentiation has been reduced.  This has led to price being the first consideration.  Organizations understand how much capacity they need and their capacity growth rate.  Determining the cost of the solution becomes a competitive comparison but can be somewhat misleading.  The evaluation must consider other factors such as the performance required for the amount of capacity as well as costs incurred for added data services (features) that will be employed.  Price is important when the other criteria are met.

Workload Support

Workload support (applications is the term used by IT) has to do with characteristics that match the usage.  An example useful in explaining this is transaction processing with an application such as SAP.  How this system operates with an application may be a differentiating characteristic that would weigh heavily in a decision.


Related to the workloads, the performance capabilities of the storage systems have continually been one of the top considerations.  The performance can be visible in the amount of work that get accomplished, the number of users supported, the time to arrive at answer, etc.  With the widespread adoption of flash devices and NVMe protocol, the amount of performance a system is capable of achieving has changed dramatically. This has led to consolidating workloads on systems, reducing the number of systems.  Differences in evaluation of performance are measured in bandwidth and IOPS with the impact of sub-100 microsecond response times.

Data Services / Advanced Features

What were termed advanced features has undergone a terminology change to Data Services with some capabilities making this a very differentiable area.  There are many data services such as remote replication, snapshots, VMware support, and business continuity capabilities.  The list of these varies by vendor (refer to the Evaluator Group Comparison Matrices for greater details), but the consideration should be limited to those that are necessary and not ones that are unlikely to be used.


In the age of ransomware, system capabilities regarding security have become more important.  Capabilities to make operational air-gapped copies of data on a storage system are unique at this point and may be a major value in a “defense-in-depth” data protection strategy.  Vendor claims in this area regarding immutability, etc. need to be challenged.  The best method is to have the system audited to prove it will meet the technical operational air-gap copy requirement.   Without an audit, there should be a high degree of skepticism.

Conversions and Operational Procedure Changes Required

Changing vendors and storage systems may introduce extra work in making procedure changes for the operation of the new system.  Many IT organizations have optimized operations by writing scripts or using automation software that is specific to the storage system and its unique APIs.  With a new system, these will need to be converted or a new implementation that may come with the new system will need to be applied.  Changes take effort and introduce risk.  In the case of automation software that was written, the original developers may no longer be available.

Conversions and operational changes are inevitable at this point.  Promises of seamless deployments have not totally materialized.  Making a vendor and storage system change requires planning for this, both in the investment to be made and the time required to put the new system into production.

Part 4 in this series will look at some specifics in evaluating block storage systems.  Characteristics for evaluation and information sources to obtain information will be included.

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