What’s the difference between ephemeral and volume boot disks?

Different boot sources

There are several different kinds of sources to boot from in the DreamCompute dashboard, but they all need to create some sort of virtual disk for the virtual machine to boot. The virtual disk can use either ephemeral storage or volume block storage. When launching an instance, you have several Boot Source options:

  • Image: Launches an instance from the image you choose onto either an ephemeral disk or a new volume disk.
  • Instance Snapshot: Launches an instance from the instance snapshot you choose onto either an ephemeral disk or a new volume disk.
  • Volume: Launches an instance from an existing bootable volume.
  • Volume Snapshot: Creates a volume from the volume snapshot you choose and then launches an instance using that new bootable volume.

Ephemeral boot disks

Ephemeral disks are virtual disks that are created for the sole purpose of booting a virtual machine and should be thought of as temporary.

Ephemeral disks are useful if you aren’t worried about needing to duplicate an instance or destroy an instance and save the data. You can still mount a volume on an instance that is booted from an ephemeral disk and put any data that needs to be saved on it, instead of using the volume as the root of your OS.

  • Can be snapshotted: Useful for duplicating instances or having a copy of an instance at a certain point in time. Snapshots of ephemeral boot disks are stored as Images and count against DreamCompute’s Image quota.
  • Do not use up volume quota: If you have more instance quota, you can always boot it from an ephemeral disk even if you don’t have any volume quota left.
  • Are destroyed when the instance is terminated: This means you will loose your data if you want to delete an instance to free up some instance quota.

Volume Boot Disks

Volumes are a more permanent form of storage than ephemeral disks and can be used to boot from as well as a mountable block device.

Volume boot disks are useful if you need an easy way to duplicate instances and back them up with snapshots, or if you need a more reliable storage solution for your instance than an ephemeral disk. If you use them, you should plan ahead so that you have enough quota for all of the instances you want to boot.

  • Can be snapshotted: Useful for duplicating instances or having a copy of an instance at a certain point in time.
  • Does not get destroyed when you delete the instance (Unless you select the “Delete Volume on Instance Delete” option): You can delete the instance and your data will still exist as a volume that you can boot from later.
  • Uses your volume quota: This can be pricey if you have lots of instances, or take lots of snapshots.

Source – https://help.dreamhost.com/hc/en-us/articles/217701757-What-s-the-difference-between-ephemeral-and-volume-boot-disks-

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Jboss boot over the network error

rajeshkumar created the topic: jboss boot over the network error
Hi,

I am getting following error when i start jboss over the network..

./run -n http://XX.XX.XX.XX:8080/netboot

Error Log.


Regards,
Rajesh Kumar
Twitt me @ twitter.com/RajeshKumarIn

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Powerful New Amazon EC2 Boot Features – Introduction

amazon-ec2-boot-features

Today a powerful new feature is available for our Amazon EC2 customers: the ability to boot their instances from Amazon EBS (Elastic Block Store).

Customers like the simplicity of the AMI (Amazon Machine Image) model where they either choose a preconfigured AMI or upload their own AMI into Amazon S3. A wide variety of operating systems and software configurations is available for use. But customers have also asked us for more flexibility and control in the way that Amazon EC2 instances are booted such that they have finer grained control over for example what software configurations and data sets are available to the instance at boot time.

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The ability to boot from Amazon EBS gives customers very powerful control over the boot configuration of the Amazon EC2 instances. In the traditional boot process, the root partition of the image will be the local disk, which is created and populated at boot time. In the new Amazon EBS boot process, the root partition is an Amazon EBS volume, which is created at boot time from an Amazon EBS snapshot. Other Amazon EBS volumes beyond the root disk can also made part of the instance before it is booted. This allows for a very fine-grain control of software and data configuration. An additional advantage of using the Amazon EBS boot process is that root partitions are no longer constrained by the size of the local disk and can be up to 1TB in size. And the new boot process is significantly faster because a local disk no longer needs to be populated.

With this new boot process another powerful feature is available to our Amazon EC2 customers: the ability to stop an instance and restart it at a later time with the disk configuration intact. When an instance is restarted, the customer can choose to use a different instance type (e.g., with more memory or CPU), a different operating system (e.g., with new security patches installed), or add new user data. While the instance is stopped it does not accrue any usage hours and customers are only charged for the storage associated with the Amazon EBS volume. The ability to stop and restart an instance is a very powerful mechanism that makes management of instances much easier; many scenarios related to adaptive instance sizing and software management have now become much simpler.

The new boot from Amazon EBS feature is an important step in our continuing quest to remove more and more of the heavy lifting that comes with today’s computer environments.

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