When Swap Files Become “Virtual RAM”

Storage disk on blue background

Posted on Wednesday, November 14, 2018

Historically, swap files have been a “bad thing” in terms of server design and management. Shuffling RAM contents onto lower-performing disks always had a serious effect on throughput. The solution was to upgrade the RAM with OEM-approved spares, or to replace the server entirely.

 A new product from Western Digital thus presents something of a surprise.

All-new “Virtual RAM”

The Ultrastar ME200 is being billed as a “Memory Extension drive” by Western Digital. In reality, the device is just a rebadged Ultrastar SN200 SSD with some clever new software.

Installed on the drive is an all-new memory management unit (MMU), advanced software that maps the drive into the host server’s memory pool. The system uses 20 algorithms to intelligently manage data flow between DRAM and the NVMe SSD– apparently offering near-DRAM performance.

An interesting concept

To accompany the announcement, Western Digital also released some performance benchmarks. In their test, a server with 768GB RAM was compared to another fitted with 96GB + the Ultrastar ME200. There was a noticeable difference in performance– 15%– but the corresponding fall in hardware costs was significant enough to justify a reduction in throughput.

The Ultrastar ME200 could conceivably be added to legacy systems to provide a much-needed performance boost– particularly useful when OEM DRAM is too expensive, or too hard to source.

The Ultrastar drive cannot be shared with storage functions as it is a dedicated virtual RAM component. But it is recognised at both BIOS and OS levels for maximum compatibility.

Is the future Software + Hardware?

The Western Digital approach is certainly novel, but only time will tell if the software + hardware paradigm gains traction in the storage market. WD face considerable pressure, for instance, from the Intel Xpoint technology, a competitor offering that also narrows the performance gap between DRAM and storage.

It will be interesting to see if Seagate or any other manufacturers release a stop-gap software + hardware solution.

In the meantime, CDS can help with your more traditional storage needs. Please give us a call to discuss how to increase performance of your assets– or to source OEM-approved spares to upgrade your post-warranty systems.

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