Tiered storage can help more businesses save on data management and handling, but not every customer will know where to start, suggests Hyper-V and VMware backup provider Altaro.
Blogging for Altaro’s Hyper-V Dojo, Symon Perriman has explained how to create and manage hot and cold tiered storage to get the benefits. Recent Windows Server releases include storage management features like deduplication, replication and mirroring that can help reduce costs and vendor lock-in, he says.
“Windows Server now offers a much-requested feature, the ability to move files between different tiers of ‘hot’ (fast) storage and ‘cold’ (slow) storage,” writes Perriman. “Files which are frequently accessed can be optimised to run on the hot storage, such as faster SSDs. Meanwhile, files which are infrequently accessed will be pushed to cold storage, such as older or cheaper disks.”
This is the tiering storage concept, using features like deduplication to maximise storage capacity and reduce cost. Storage is pooled using Windows Server’s storage spaces, with no need to manage individual drives. File placement is controlled by the ReFS (Resilient File System), a file system which can rotate data between hot and cold tiers as required, based on usage.
Other key components include Storage Spaces Direct (S2D) which lets servers with DAS (direct-attached storage) drives support failover clustering.
“Previously, highly-available file server clusters required some type of shared storage on a SAN or used an SMB file share, but S2D allows for small local clusters which can mirror the data between nodes,” explains Perriman.
To use tiered storage with ReFS, you can also use mirror-accelerated parity. From Windows Server 2016 and 2019 onwards, S2D provides “decent” storage capacity by using mirroring with a parity drive to help prevent data loss. In the past, mirroring and parity conflicts meant you needed to choose one or the other, he says.
“Mirror-accelerator parity works with ReFS by taking writes and mirroring them (hot storage), then using parity to optimise their storage on disk (cold storage). By switching between these storage optimisation techniques, ReFS provides admins with the best of both worlds,” says Perriman.
When configuring tiered storage, Microsoft recommends allocating 20% to hot storage and 80% to cold. If you have a lot of archival files, however, you might need even more cold memory. Resizing ratios doesn’t change the size of the partition or volume.
“Remember that with a storage pool you can combine multiple disk types under the same abstracted storage space,” he says.
Perriman offers some PowerShell cmdlets to demonstrate configuration of a 1000GB disk.
Partitions and volumes can be adjusted using Resize-Volumes cmdlets, with even more optimisation available by adjusting the aggressiveness of the rotation, he adds.
“By default, the hot storage will wait until 85% of its capacity is full before it begins to send data to the cold storage,” says Perriman. “If you have fewer write requests and want to keep data in hot storage longer you can increase this value. Since this is an advanced configuration option, it must be configured via the registry on every node in the S2D cluster, and it also requires a restart.”
Altaro adds VM backup subscriptions
In other news, Altaro has made its VM Backup offering available as a subscription service.
“Some of our customers find subscription services more affordable, making it simpler to manage and predict expenses, and easier to obtain approval as they fall under opex rather than capex. They can pay annually, and scale up or down as needed,” explains Altaro CEO David Vella in the announcement.
“We have been in close contact with our partners and customers during these challenging times and wanted to be responsive to their feedback and requests. This way, they can still benefit from reliable, reputable VM backup, recovery and replication, without overstretching their budgets.”
A subscription to Altaro VM Backup includes 24/7 technical support plus latest features and patch fixes, starting from five VMs a year.
Altaro offers backup and recovery solutions to companies, resellers and MSPs for Hyper-V and VMware virtual environments, Microsoft Office 365 mailboxes, OneDrive and SharePoint, roaming and on-premise endpoints such as network desktops and laptops, and physical Windows servers.