Trends in Storage – Transition to All-Flash & beyond

The use of flash in storage devices is not new; however, we are now seeing the increased use of flash compared to disk storage.  Almost all storage companies now provide hybrid solutions that have a mix of SSDs and HDDs in their boxes.  Those that don’t are completely switching over to leverage the advantages of SSDs.  As the costs of SSDs plummet further, we will see SSD being used more aggressively in storage boxes.  Companies like Avere, Marvell, Starboard are providing unique offerings with SSD supported devices. Soon, companies like XtremIO (recently acquired by EMC) with all-flash products will enter the fray.  Looking forward, there are some new memory technologies that could potentially replace flash in years to come.

Flash Technology

NAND flash technology is only a decade old. However, it has already gained significant traction due to its mechanical characteristics and performance. SSDs with NAND flash have a number of advantages over HDD devices. Some of them are:

  • Power savings of 2x
  • No noise
  • No vibration(since there are no moving parts)
  • Very little heat
  • About 30% faster than HDDs
  • Magnetic field safe

SSD costs, although reducing, are still higher than HDD costs. This is the only factor that is preventing a complete replacement of HDDs in storage products. See this article in Storage Review for a detailed comparison between SDD and HDD drives.

SSD offerings

Storage companies are already offering several solutions built around SSD drives in their storage servers and boxes. There are also ways in which SSDs can be utilized in the storage environment in a transitional manner while improving value proposition for customers.

Major vendors like EMC Corp. and NetApp Inc. have placed flash memory in their storage arrays and designed controller software to use the flash memory as a cache. EMC Fast (Fully Automated Storage Tiering) Cache improves the performance of existing SATA drives/FC and SAS drivers as well. NetApp on the other hand uses FlashCache to improve performance. This also compensates for the performance penalty due to their de-duplication technology (designed for capacity optimization). See this article by Joerg Hallbauer for a nice comparison between these technologies.

Avere Systems and Marvell, take a different standpoint. Avere’s FXT caching appliance sits between NAS arrays and clients.  Ron Bianchini, founder and CEO of Avere Systems claims that the appliance delivers 50 times lower access latency then existing NAS devices. Marvell’s Dragonfly VSA is designed to be placed inside the server. It uses NVRAM and SSD caches for random write handling.

Storage vendors are also transforming their fixed RAID systems to automatically tiered storage devices.  EMC’s FAST Virtual Pool is an example of a device in this category.  It places only data that requires high speed access to SSD drives while data that is only moderately used is placed on SAS drives.  Starboard Storage in its AC72 system also utilizes SSDs and HDDs with automated tiering. Data that is less frequently used is targeted towards HDDs.

By moving “hot” data to faster storage devices, tiered storage systems can perform faster than similar devices without the expense of widely deploying these faster devices.  Conversely, automated tiering can be more energy- and space-efficient because it moves “bulk” data to slower but larger-capacity drives.

Storage vendors are also coming up with “All Flash” products – despite the costs involved—to cater to customers that demand speed.  EMC announced “Project X” recently that utilises XtremIO technology to provide an all flash storage box that is fast, and uses in-line de-dup technology.

Future Memory Technologies

Even while we are considering the current industry trend towards flash SSD based devices, there are future technologies that could disrupt flash. Potential successor technologies to flash include Resistive RAM (RRAM), Magnetoresistive RAM (MRAM) and Phase-change memory (PCM).  But, more about these memory types in a different article.

Usage of flash in storage devices is not new; however, we are witnessing increasing usage of flash as compared to disk storage as a trend. Almost all companies now are providing hybrid solutions that have a mix of SSDs and HDDs in their boxes. Those that don’t are transitioning over to leverage the advantages of SSDs. As costs of SSDs plummet further, we will see SSD being used more aggressively in storage boxes. This short article talks about the current state of products in this space and how companies like Avere, Marvell, Starboard are providing unique offerings with SSD supported devices. Very soon we will also have companies provide all-flash products as is evidenced by acquisition of XtremIO by EMC. We briefly also touch upon which memory technologies can potentially replace flash in years to come.

Flash Technology

NAND flash technology is only a decade old. However, it has already gained significant focus due to its mechanical characteristics and performance. SSDs with NAND flash have a number of advantages over HDD devices. Some of them being:

  • Factor x2 Power savings
  • No noise devices
  • No vibration devices (since there are no moving parts)
  • Very little heat produced
  • About 30% faster than HDDs
  • Magnetic field safe

However, currently SSD costs, although reducing, are still higher than HDD costs. This is the only factor that is preventing a complete replacement of HDDs in storage products. See article on Storage Review for a detailed comparison between SDD and HDD drives.

SSD offerings

Storage companies are already offering several solutions around SSD drives in their storage servers and boxes. There are ways in which SSDs can be utilized in storage environment in a transitional manner while improving value proposition for customers.

Major vendors like EMC Corp. and NetApp Inc. have placed flash memory in their storage arrays and designed controller software to use it as a cache. EMC Fast (Fully Automated Storage Tiering) Cache improves the performance of existing SATA drives/FC and SAS drivers as well. NetApp on the other hand uses FlashCache to improve performance. This also compensates the performance penalty caused due to their de-duplication technology which is designed for performing capacity optimization. See article by Joerg Hallbauer for a nice comparison between these technologies.

Avere Systems and Marvell Technology Group Ltd, take a different standpoint. Avere’s FXT caching appliance sits between NAS arrays and clients. Ron Bianchini, founder and CEO of Avere Systems claims that the appliance delivers 50 times lower access latency using customer’s existing NAS devices. Marvell’s Dragonfly VSA is designed for placement inside the server itself. It uses NVRAM and SSD caches for random write handling.

Storage vendors are also transforming their fixed RAID systems to automatically tiered storage devices.

EMC’s FAST Virtual Pool is an example of a device in this category. It places only data that requires high speed access to SSD drives while data that is only moderately used is placed on SAS drives.

Starboard Storage in its AC72 system also utilizes SSDs and HDDs with automated tiering. Data that is less frequently used is targeted towards HDDs.

By moving “hot” data to faster storage devices, tiered storage systems can perform faster than similar devices without the expense of widely deploying these faster devices. Conversely, automated tiering can be more energy- and space-efficient because it moves “bulk” data to slower but larger-capacity drives.

Storage vendors are also coming up with “All Flash” products despite the costs involved to cater to customers that demand speed. EMC announced “Project X” recently that utilises XtremIO technology to provide all flash storage box that is fast, and uses in-line de-dup technology.

Future Memory Technologies

Even while we are considering the current industry trends towards flash SSD based devices, there are future technologies that can disrupt this current trend towards flash. Potential successor technologies to flash include Resistive RAM (RRAM), Magnetoresistive RAM (MRAM) and Phase-change memory (PCM). But, more about these memory types in a different article.

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