Dell EMC PowerProtect DDVE in the Azure Cloud 7.9 Installation and Administration Guide

Data disk limitations

https://docs.microsoft.com/en-us/azure/azure-subscription-service-limits provides details about Azure limitations. Observe the following requirements for planning storage expansion:

• The maximum size of each disk is 4 TB, the recommended size is 1 B for performance consideration.
• VM size determines the maximum number of data disks for the Azure VM instances that DDVE uses. See Virtual Machine Sizes for data disk limitations (the root disk and resource disk that Azure adds are not counted in this limitation). The NVRAM emulation disk is also counted as one data disk for Azure. For example, for one DDVE instance in Azure that supports up to 16 TB block storage, the maximum number of data disks = (32 - 1) = 31.

Expanding DDVE on block storage

DDVE capacity can be dynamically expanded by adding more data disks to the instance. Increments of 1 TB are recommended. When the maximum capacity that the instance supports is reached, you must upgrade the VM to a larger size before adding more storage to the system.

Do not manually set or change the spindle group setting when adding storage. DDVE automatically assigns the spindle group.

Expanding DDVE on hot blob storage

The local block storage is used for caching metadata. Based on different workloads, the needed metadata size varies. Dell Technologies recommends that you configure the metadata storage size as 10% of total capacity, which is enough for most workloads. For workloads with a higher deduplication ratio, more metadata is needed.

Metadata storage can be dynamically expanded. When the metadata storage space usage exceeds 80%, an alert is raised. Immediately add a metadata disk to the DDVE to avoid running out of space. The DDOS Administration Guide provides a procedure for expanding storage. Dell Technologies recommends that you always use a 1 TB disk.

Hot blob storage location

When you use DDVE on hot blob storage, ensure that your hot blob storage account and DDVE instance are in the same region. Configuring the VM and storage account in different regions can result in lower performance and higher costs.

Create separate storage account for each DDVE

Azure infrastructure throttles each storage account, and each storage account has its own IOPS and throughput limits. For best performance, create a separate storage account for each DDVE.

Disk caching

Host-caching is not supported for data disks (DDVE on block storage) or metadata disks (DDVE on hot blob storage). Changing the cache setting of an Azure disk detaches and reattaches the target disk. For the operating system disk, the VM is restarted. Ensure that you stop all applications and services that this disruption might affect before changing the disk cache setting.

Converting from evaluation to production

Rather than convert an evaluation version of DDVE to a production version, Dell Technologies recommends a fresh deployment. If you decide to convert from an evaluation to production version, Dell Technologies recommends that you:

• Destroy the existing file system
• Delete small data disks (not the root, NVRAM disks)
• Configure new disks according to the recommendations in this guide