How APM Tools and High Availability Clusters Improve Network Resilience

Network resilience refers to a network’s ability to maintain connectivity and continue functioning even when disruptions occur. For organizations that rely heavily on technology, maintaining this resilience has become an operational necessity. A recent analysis by Siemens found that even a single hour of downtime can cost organizations millions of dollars. Downtime can interrupt production, breach service level agreements (SLAs), halt transactions, and generate significant expenses related to overtime, external consultants, incident investigations, and regulatory penalties.

In some industries, such as financial services, the consequences of weak network resilience can ripple far beyond a single organization. Global economies depend on financial institutions that operate stable and efficient IT systems capable of supporting trillions of dollars in transactions each year. Any perception that these systems are unreliable can affect entire markets. As a result, regulatory bodies such as the Basel Committee and the US Federal Reserve enforce strict standards around operational resilience. Similarly, organizations operating in sectors such as healthcare, telecommunications, and critical infrastructure must follow guidelines that ensure strong levels of network reliability and continuity.

Resilient Organizations Invest in Smart Infrastructure

IT environments, whether deployed on-premises, in the cloud, or across hybrid architectures, continue to grow in size and complexity. As a result, IT teams need tools that provide better visibility and enable smarter decision-making. Modern IT operations rely increasingly on data-driven insights and automation to support the work of IT professionals.

For this reason, forward-thinking organizations are investing in technologies that strengthen resilience and improve operational awareness. Two technologies that work particularly well together are application performance monitoring (APM) platforms and high availability (HA) clustering solutions.

APM tools play a key role by collecting and analyzing performance data across the IT environment. This data helps organizations better understand the health and behavior of their systems, allowing administrators to establish more accurate thresholds for alerts and automated responses. High availability clusters complement this capability by ensuring services can fail over to standby systems when disruptions occur. These clusters may rely on shared storage in traditional SAN-based environments or use software-based SANless clustering that replicates data between nodes.

Combining APM and HA for Greater Network Resilience

When APM tools and HA clusters are deployed together, organizations gain stronger capabilities for improving network resilience. Monitoring insights from APM platforms can inform automation and operational decisions, while HA clusters ensure workloads continue running even when failures occur.

This combination supports capabilities such as automated failover, predictive analytics, self-healing processes, and faster incident response. These capabilities help organizations maintain higher uptime and deliver consistent application performance.

In multi-cloud environments, this approach becomes even more valuable. If a cloud provider experiences an outage, services can fail over to an alternate cloud environment. Organizations can also distribute workloads across multiple clouds to eliminate single points of failure and improve overall system resilience.

As enterprises continue moving toward more autonomous IT operations, the data gathered by APM tools provides a detailed view of system performance and health. This information allows IT teams to define precise policies and operational thresholds, enabling confident and informed decision-making when issues arise.

Using Monitoring Data to Support Failover Decisions

Consider a scenario where an IT administrator must decide whether to initiate a failover to prevent a potential outage. The cost of manually initiating the failover may exceed $50,000 due to operational disruption and recovery procedures. However, waiting too long could result in a far more expensive failure.

Without clear data, decision-makers may hesitate to act. They may worry about triggering a costly intervention based on incomplete information or intuition alone. Reliable performance data helps eliminate this uncertainty by providing objective evidence that supports informed action.

With accurate monitoring insights, teams can determine whether system conditions truly justify failover. If intervention becomes necessary, they can confidently act with data-backed justification.

This is where the combination of APM tools and HA clustering becomes particularly valuable. Together, they help maintain service continuity when performance degradation, unexpected incidents, or large-scale disruptions threaten operations. APM monitoring provides visibility into the health of infrastructure components, allowing administrators to identify issues early and respond before downtime occurs. If failover becomes necessary, the decision is guided by clearly defined parameters based on the organization’s risk tolerance.

The Advantages of HA Clusters with APM

When HA clusters are integrated with an organization’s APM platform, mission-critical applications and services can fail over automatically with minimal disruption. Automated failover reduces the risk of delays or errors that can occur during manual recovery efforts and allows operations to continue while underlying issues are addressed.

Today, many organizations are adopting SANless clustering approaches. These solutions provide the same failover capabilities as traditional SAN-based clusters but without the cost and complexity of shared storage infrastructure. SANless clusters replicate data across nodes and operate efficiently in on-premises, cloud, or hybrid environments.

They also support geographically distributed deployments across multiple data centers or regions, which is essential for effective disaster recovery planning.

Whether an organization operates in a highly regulated industry or simply wants to strengthen its reliability and operational stability, combining APM monitoring with high availability clustering offers a practical and effective strategy. Together, these technologies provide a straightforward and cost-efficient way to improve uptime, strengthen resilience, and meet the growing expectations for reliable IT services.

Strengthen Network Resilience with High Availability Clustering

Keep your applications running even when failures occur. SIOS high availability clustering helps organizations maintain uptime, automate failover, and protect critical systems from downtime.

Request a demo to see how SIOS can help strengthen your network resilience.

Reproduced with permission from SIOS

High Availability Clusters in VMware vSphere without Sacrificing Features or Flexibility

Six key facts you should know about high availability protection in VMware vSphere

Many large enterprises are moving important applications from traditional physical servers to virtualized environments, such as VMware vSphere in order to take advantage of key benefits such as configuration flexibility, data and application mobility, and efficient use of IT resources. Realizing these benefits with business-critical applications, such as SQL Server or SAP can pose several challenges.

This paper explains these challenges and highlights six key facts you should know about HA protection in VMware vSphere environments that can save you money.

New Options for High Availability Clusters, SIOS Cements its Support for Microsoft Azure Shared Disk

Microsoft introduced Azure Shared Disk in Q1 of 2022. Shared Disk allows you to attach a managed disk to more than one host. Effectively this means that Azure now has the equivalent of SAN storage, enabling Highly Available clusters to use shared disk in the cloud!

A major advantage of using Azure Shared Disk with a SIOS Lifekeeper cluster hierarchy is that you will no longer be required to have either a storage quorum or witness node to avoid so called split-brain – which occurs when the communication between nodes is lost and several nodes are potentially changing data simultaneously. Fewer nodes means less cost and complexity.

SIOS has introduced an Application Recovery Kit (ARK) for our LifeKeeper for Linux product; called LifeKeeper SCSI-3 Persistent Reservations (SCSI3) Recovery Kit that allows Azure Shared Disks to be used in conjunction with SCSI-3 reservations. This ARK guarantees that a shared disk is only writable from the node that currently holds the SCSI-3 reservations on that disk.

When installing SIOS Lifekeeper, the installer will detect that it’s running in Microsoft Azure EC2 and automatically install the LifeKeeper SCSI-3 Persistent Reservations (SCSI3) Recovery Kit to enable support for Azure Shared Disk.

Resource creation within Lifekeeper is straightforward and simple (Figure 1). Once locally mounted, the Azure Shared Disk is simply added into Lifekeeper as a file-system type resource. Lifekeeper will assign it an ID (Figure 2) and manage the SCSI-3 locking automatically.

Figure 1] Creation of /sapinst within Lifekeeper.

Figure 2] /sapinst created and extended to both cluster nodes.

SCSI-3 reservations guarantee that Azure Shared Disk is only writable on the node that holds the reservations (Figure 3). In a scenario where cluster nodes lose communication with each other the standby server will come online, causing a potential split-brain situation. However, because of the SCSI-3 reservations only one node can access the disk at a time, which prevents an actual split-brain scenario. Only one system will hold the reservation and it will either become the new active node (in this case the other will reboot) or remain the active node. Nodes that do not hold the Azure Shared Disk reservation will simply end up with the resource in an “Standby State” state because they cannot acquire the reservation.

Figure 3] Output from Lifekeeper logs when trying to mount a disk that is already reserved.

Link to Microsoft’s definition of Azure Shared Disks https://docs.microsoft.com/en-us/azure/virtual-machines/disks-shared

At present SIOS supports Locally-redundant Storage (LRS) and we’re working with Microsoft to test and support Zone-Redundant Storage (ZRS). Ideally we’d like to know when there is a ZRS failure so that we can fail-over the resource hierarchy to the most local node to the active storage.

At present SIOS is expecting the Azure Shared Disk support to arrive in its next release of Lifekeeper 9.6.2 for Linux, Q3 2022.

Reproduced with permission from SIOS