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All about Disk Drives

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ALTO is a disk based archiving technology, but what type of disks do we use? Do we supply them ready installed in our ALTO enclosures, or can you purchase them locally and install them yourself? Can you mix disks from different vendors, with different capacities? On this page we try to answer all your disk-based questions. In short, the answer is simple - ALTO enables you to purchase disks as you need them, with no single vendor lock-in, and the ability to install larger capacity disks as they become available. 


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Low-Cost 'Off-the-Shelf'
Commodity Disk Drives


The disk drives used in the ALTO Archive are standard commercially available models available from leading suppliers including Western Digital, Seagate, HGST and Toshiba. These are the leading vendors actively developing high capacity, low power sub-nearline disk drives, driven by the demand for environmentally sensitive end economically viable long-term storage.


Disk Archive Corporation tests and type-approves disks for use with ALTO, adding new drive types to a Qualified Disk List which is updated quarterly to reflect new introductions. ALTO-III can be purchased “diskless” for Customers who prefer to purchase their preferred disks from local suppliers, taking advantage of local pricing and the convenience of local warranty support. Alternatively ALTO-ARX is supplied populated with disk drives to provide 50 TB, 100 TB or 150 TB Secure Replicated Storage.

Application Optimised

ALTO-III, the fully scalable Enterprise Archive has three principal areas of application within a facility for Active Storage, General Purpose Storage and Deep Archive Storage. Customers can use dedicated ALTO systems configured and populated with suitable disks for each functional area or Partitions can be created within a larger ALTO System for each functional area and the Partitions configured as required. ALTO supports mixed drive types and capacities within a single system, so that the choice of disk can be tailored to the performance, capacity and budget for each user. ALTO-ARX is supplied factory populated with General Purpose Disks described below to achieve the target capacity.

ALTO is compatible with conventional PMR disks and more specialist SMR disk technology developed to further increase capacity and reduce cost per TB. Deep Archive disks are write optimised to increase writing speed compared to less important read access. Files can be deleted to recover space and data can be re-written but with lower writing speed, making these drives highly suitable for deeper archive applications where the stored files are not frequently overwritten. They are most suitable for preservation applications with up to 180TB per year throughput per disk, offering a very significant cost reduction. The security and surveillance industry drives demand for high volumes of write optimised storage. ALTO deep archives take advantage of these economies of scale.

Where an ALTO-III is likely to be used in areas of very high demand, it is possible to use higher performance disks to provide a shorter spin-up characteristic and faster data transfer rate. For high demand lower capacity Helium drives offer the best spin-up performance, and lowest power consumption per drive. In ALTO-III, the Disk type used can be further fine tuned, for example with Primary Replicas on fast Disks and Secondary Replicas on Slower and hence lower cost disks. This flexibility derives directly from the Replication principal used in ALTO, along with the ability to distribute replicas in geographically divers locations and shelf storage. ALTO disks can be opened externally using a standard Windows, MacOS or Linux Computer 

Disk Drives for
General Purpose Storage

Disk Drives for
Deep Archive Storage

Disk Drives for
High Availability Archives


This class of disk is a sub-nearline NAS disk optimised for higher capacity, trading off speed against power consumption and cost. They are designed for high bi-directional workloads and are most frequently used in areas with a managed Archive and Restore demand, such as TX Archives demand. Typically these disks have a nominal capacity of 10TB, 12TB, 14TB and 16 TB per disk drive for high-storage density approaching 1Petabyte per 4RU enclosure. ALTO is compatible with air-filled and helium-filled disk drives from the four leading vendors. Helium filled disks provide a totally inert environment for the disk drives internal components, extending data life on the disk platters and improving storage density 

Any Disk from Any Vendor of any Size in any Slot – No disk vendor dependency

ALTO-III has the unique ability to mix different disk capacities, different disk speeds and different recording technologies from different vendors on a slot-by-slot basis allowing systems to be configured for the precise requirements of multiple user groups within a single system. A wide range of disks are available from the Qualified Disk List allowing storage to be optimised for performance, capacity, vendor and budget, tracking disk capacity and recording technologies enhancements as they emerge.

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Buy As You Go - Disk Drives as an Operational Expense rather than a Capital Cost

Due to the unique architecture of ALTO-III, disk drives can be purchased and added to the configuration on a buy-as-you-go basis in keeping with our future-proof Enterprise Value Proposition. Customers have the option to purchase the disk drives, as an Operational Expense rather than part of the Capital Investment. ALTO-III supports any type-approved disk, from any vendor, in any disk slot for compatibility with larger disk drives as they come to market and a guarantee of no single vendor lock-in. ALTO-ARX is supplied ready populated with disks, but in the long term, any similar or larger capacity drive can be used as a replacement, guarding against vendor lock-in and obsolescence

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