Virtual Disk Bad Block Management

[Madox Valdivia]

But all disk are in Firmware state: Online, Spun Up.
Also there is not a single ATA read or write error in any disk in the raid (I check them with smartctl -a -d sat+megaraid,N -H /dev/sda). The only strange thing is in the output in

How could there be bad blocks in a Virtual Drive, which is in optimal state and no disk is broken or even with a single error? I tried "Consistency Check", but it finished successfully and the errors are still in dmesg. Could Someone help me to figure it out what is wrong with my raid?

If the CU detects a media error on the source drive during rebuild, it initiates a sector read for that block. If the sector read fails, the CU adds entries to the Soft Bad Block Management (SBBM) table, writes this table to the target drive, and displays an error message.

Whether the block device is provided to the guest in read-only or read-write mode. Supported values are ro or r for read-only, and rw or w for read/write access. Default is ro for devtype=cdrom, and rw for other device types.

Specifies that target is not a normal host path, but rather information to be interpreted by the executable program. The specified script file is looked for in /etc/xen/scripts if it does not point to an absolute path. These scripts are normally called block-.

While it is always possible to add new block devices to a VM Guest system, it is sometimes more desirable to increase the size of an existing block device. In case such a system modification is already planned during deployment of the VM Guest, some basic considerations should be done:

Make sure that the file system to be used can be resized. Sometimes, for example with Ext3, some features must be switched off to be able to resize the file system. A file system that can be resized online and mounted is XFS. Use the command xfs_growfs to resize that file system after the underlying block device has been increased in size. For more information about XFS, see man 8 xfs_growfs.

When resizing an LVM device that is assigned to a VM Guest, the new size is automatically known to the VM Guest. No further action is needed to inform the VM Guest about the new size of the block device.

These scripts could formerly only be used with xl or libxl using the disk configuration syntax script=. They can now be used with libvirt by specifying the base name of the block script in the element of the disk. For example:

As organizations continue to migrate to the cloud, they often find themselves facing the challenge of seamlessly transferring and managing their existing block volumes. Whether it's for migrating on-premises workloads, implementing disaster recovery strategies, or optimizing their cloud infrastructure, the ability to import virtual disks with ease becomes a critical need.

An Oracle Cloud Infrastructure region is a localized geographic area that contains one or more data centers, called availability domains. Regions are independent of other regions, and vast distances can separate them (across countries or even continents).

A VCN is a customizable, software-defined network that you set up in an Oracle Cloud Infrastructure region. Like traditional data center networks, VCNs give you complete control over your network environment. A VCN can have multiple non-overlapping CIDR blocks that you can change after you create the VCN. You can segment a VCN into subnets, which can be scoped to a region or to an availability domain. Each subnet consists of a contiguous range of addresses that don't overlap with the other subnets in the VCN. You can change the size of a subnet after creation. A subnet can be public or private.

The DevOps service is an end-to-end, continuous integration and continuous delivery (CI/CD) platform for developers that facilitates the process of building artifacts and deployment to OCI compute services (Functions, Oracle Container Engine (OKE) or Compute Instances).

Oracle Cloud Infrastructure (OCI) Compute VMs provide secure and elastic compute capacity in the cloud for workloads ranging from small development projects to large-scale, global applications such as real-time communication platforms. Flexible shapes enable users to optimize VM resources with customized processor and memory values for improved price performance.

When you create a VCN, determine the number of CIDR blocks required and the size of each block based on the number of resources that you plan to attach to subnets in the VCN. Use CIDR blocks that are within the standard private IP address space.

Select CIDR blocks that don't overlap with any other network (in Oracle Cloud Infrastructure, your on-premises data center, or another cloud provider) to which you intend to set up private connections.

It is strongly recommended for the user who deploys the stack to be a member of the administrators group. In case the user exposes Apache Airflow to the internet using the allowed_source_cidr variable, it is strongly recommended to fill in specific IP, subnet CIDR block.

The instance running Apache Airflow and temporary worker instances are authorized using a dynamic group to manage instances, block volumes and read objects in the compartment they belong to. The function is authorized to perform read operations against the object resources in the compartment.

The Apache Airflow API on port 8080 of the Apache Airflow instance is reachable from the internet only when a new VCN is created, the instance has a public IP address and the allowed_source_cidr variable includes the source IP from where the connection is attempted.

A temporary compute instance is created to handle each virtual disk import operation to Oracle Cloud Infrastructure Block Volumes. On successful completion of the workflow the instance is terminated.

Azure managed disks are block-level storage volumes that are managed by Azure and used with Azure Virtual Machines. Managed disks are like a physical disk in an on-premises server but, virtualized. With managed disks, all you have to do is specify the disk size, the disk type, and provision the disk. Once you provision the disk, Azure handles the rest.

The available types of disks are ultra disks, premium solid-state drives (SSD), standard SSDs, and standard hard disk drives (HDD). For information about each individual disk type, see Select a disk type for IaaS VMs.

Alternatively, you could use an Azure Elastic SAN as your VM's storage. An Elastic SAN allows you to consolidate the storage for all your workloads into a single storage backend and can be more cost effective if you've a sizeable amount of large scale IO-intensive workloads and top tier databases. To learn more, see What is Azure Elastic SAN?

Managed disks are designed for 99.999% availability. Managed disks achieve this by providing you with three replicas of your data, allowing for high durability. If one or even two replicas experience issues, the remaining replicas help ensure persistence of your data and high tolerance against failures. This architecture has helped Azure consistently deliver enterprise-grade durability for infrastructure as a service (IaaS) disks, with an industry-leading ZERO% annualized failure rate. Locally redundant storage (LRS) disks provide at least 99.999999999% (11 9's) of durability over a given year and zone-redundant storage (ZRS) disks provide at least 99.9999999999% (12 9's) of durability over a given year.

Using managed disks, you can create up to 50,000 VM disks of a type in a subscription per region, allowing you to create thousands of VMs in a single subscription. This feature also further increases the scalability of virtual machine scale sets by allowing you to create up to 1,000 VMs in a virtual machine scale set using a Marketplace image or Azure Compute Gallery image.

Managed disks are integrated with availability sets to ensure that the disks of VMs in an availability set are sufficiently isolated from each other to avoid a single point of failure. Disks are automatically placed in different storage scale units (stamps). If a stamp fails due to hardware or software failure, only the VM instances with disks on those stamps fail. For example, let's say you have an application running on five VMs, and the VMs are in an Availability Set. The disks for those VMs won't all be stored in the same stamp, so if one stamp goes down, the other instances of the application continue to run.

Managed disks support Availability Zones, which is a high-availability offering that protects your applications from datacenter failures. Availability Zones are unique physical locations within an Azure region. Each zone is made up of one or more datacenters equipped with independent power, cooling, and networking. To ensure resiliency, there's a minimum of three separate zones in all enabled regions. With Availability Zones, Azure offers industry best 99.99% VM uptime SLA.

To protect against regional disasters, Azure Backup can be used to create a backup job with time-based backups and backup retention policies. This allows you to perform VM or managed disk restorations at will. Currently Azure Backup supports disk sizes up to 32 tebibyte (TiB) disks. Learn more about Azure VM backup support.

Azure Backup offers Azure Disk Backup as a native, cloud-based backup solution that protects your data in managed disks. It's a simple, secure, and cost-effective solution that enables you to configure protection for managed disks in a few steps. Azure Disk Backup offers a turnkey solution that provides snapshot lifecycle management for managed disks by automating periodic creation of snapshots and retaining it for configured duration using backup policy. For details on Azure Disk Backup, see Overview of Azure Disk Backup.

You can use Azure role-based access control (Azure RBAC) to assign specific permissions for a managed disk to one or more users. Managed disks expose a variety of operations, including read, write (create/update), delete, and retrieving a shared access signature (SAS) URI for the disk. You can grant access to only the operations a person needs to perform their job. For example, if you don't want a person to copy a managed disk to a storage account, you can choose not to grant access to the export action for that managed disk. Similarly, if you don't want a person to use an SAS URI to copy a managed disk, you can choose not to grant that permission to the managed disk.

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