Availability Insights

Snapshots needed for EBS volumes

In order to prevent losing important data, it is essential to back up your EBS Volumes. EBS Snapshots enable the creation of virtual copies of EBS Volumes at a specific point in time. A snapshot comprises data blocks that are incrementally saved to Simple Storage Service (S3), meaning that only the blocks on the device that have changed since your last snapshot are saved. For that reason, EBS Snapshots can be an efficient way to back-up the data in EBS Volumes.

For typical data backup procedures, EBS Snapshots offer an adequate instrument to perform backup of EBS Volumes. When using EBS Snapshots as part of a backup procedure, an important parameter to take into consideration when defining your policy is the frequency of snapshots. Factors like the type of data stored in the EBS volumes, its volatility, the amount of data, and others, are key in determining the frequency in which EBS Snapshots should be created.

Compute Utilization Efficiency (High Load)

Newvem continuously monitors servers’ CPU load and notifies on high CPU loads.  We consider an average CPU load of 80% and above as a high load. As high CPU load can lead to a major service availability risks, which results in service degradation. In order to protect the system one should consider changing the instance size or implementing a different scaling method. We suggest that you either:

  • Scale up your computer instances – vertical scaling; move your workload to larger servers.
  • Scale out your compute instances – horizontal scaling; use additional servers.
  • Auto-scaling – AWS offers the ability to dynamically and automatically scale up or down according to conditions you define. With Auto Scaling, you can ensure that the number of Amazon EC2 instances you’re using increases seamlessly during demand spikes to maintain performance, and decreases automatically during demand lulls to minimize costs. Auto Scaling is enabled by Amazon CloudWatch and available at no additional charge beyond Amazon CloudWatch fees.

EBS Volumes have No Backup

An EBS Snapshot is a copy of an EBS volume at a particular point in time. A snapshot can be taken of a volume, regardless of whether or not the volume is attached to a running instance. A snapshot comprises data blocks that are incrementally saved to Simple Storage Service (S3), meaning that only the blocks on the device that have changed since your last snapshot are saved. When saved to S3, the snapshot is assigned a timestamp and unique AWS ID. 

Servers are not Balanced across Multiple Availability Zones

AWS Elastic Load Balancing (ELB) automatically distributes incoming traffic to your application to multiple EC2 instances that are attached to your Elastic Load Balancer. At any time, Elastic Load Balancing detects the unhealthy instances in the pool, and distributes the incoming traffic only to the healthy instances until the unhealthy ones are restored.

In order to achieve greater fault tolerance and thus higher availability, it is recommended to distribute your instances in different geographical zones so that if all the instances in a single datacenter are not healthy, as may occur when there is an outage, your application will run in a data center in a different zone.

AWS Scheduled Maintenance Events

AWS schedules rebooting of host hardware and/or instances in order to perform maintenance on them, such as installing security patches and updates. Scheduled reboots can lead to service disruption.

Newvem checks for scheduled reboot events of your cloud servers and lets you understand the availability issues related.

To avoid service disruption, we suggest that you proactively re-launch your servers before AWS reboots them. That will possibly give you an entirely new server on new infrastructure hardware that does not require an AWS-scheduled reboot.

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