Feature Highlights


  • No special disk hardware required
  • Works with existing equipment in your data center and future additions
    • Not limited to a single hardware manufacturer 
    • Not limited to disk trays within one enclosure
  • You select which disks make up each tier (e.g., high performance, mid-range, low cost)
  • Adapts to provide most demanding workloads with speediest response
  • Demotes infrequently accessed information to more cost-effective disks
  • Access frequency determines which disk blocks should be moved into a different tier 
    • Senses sustained hot spots within files or databases 
    • Works at sub-LUN level for best granularity
  • Override automatic migration for special circumstances


AUTO-TIERING

Enterprise-wide Management: Optimizes across different types of storage by dynamically choosing between fast / expensive assets (e.g., SSDs) and lower cost / higher capacity storage resources

Automated storage tiering distills down to monitoring I/O behavior, determining frequency of use, then dynamically moving blocks of information to the most suitable class or tier of storage device (SSD, Fast Disk, Capacity Disk, Gateway to Cloud Storage Provider). DataCore™ SANsymphony™-V software automatically “promotes” most frequently used blocks to the fastest tier, whereas least frequently used blocks get “demoted” to the slowest tier. Everything else floats to the middle.

Auto-Tiering

Of course, there will be exceptions, especially when you need to assign high performance storage to an infrequently used volume, as in special end-of-quarter general ledger processing. In these cases, you can pin specific volumes (virtual disks) to a tier of your choosing, or define an “affinity” to a particular tier. Only if that tier is completely exhausted, will a lower tier be chosen.

Say the disk capacity in your data center is split among 4 classes of disks, 3 classes within your local data center and 1 or more classes located remotely for archival or backup data using Cloud based pay-as-you-go storage capacity:

  • 5% Flash SSD [ Fastest, most expensive ] >> Tier 1
  • 35% SAS HDD [ Midrange, modestly priced ] >> Tier 2
  • 60% SATA HDD [ Lower cost, higher capacity ] >> Tier 3
  • Backup or Archival Cloud Storage [ Lowest cost, highest capacity ] >> Tier N

In general, you wouldn’t want to waste the premium priced SSD capacity on infrequently used blocks, so the DataCore software will keep the least active information on the lowest cost, capacity-optimized Serial ATA (SATA) disks.

Intelligent tradeoff between performance & cost

The science of automated storage tiering distills down to monitoring I/O behavior, determining frequency of use, then dynamically moving blocks of information to the most suitable class or tier of storage device. SANsymphony-V software automatically “promotes” most frequently used blocks to the fastest tier, whereas least frequently used blocks get “demoted” to the slowest tier. Everything else floats to the middle.

Of course, there will be exceptions, especially when you need to assign high performance storage to an infrequently used volume, as in special end-of-quarter processing.

In these cases, you can pin specific volumes (virtual disks) to a tier of your choosing, or define an “affinity” to a particular tier. Only if that tier is completely exhausted, will a slower tier be chosen.

In order to appreciate the financial motivation for auto-tiering, consider the price/performance differences among the three most popular classes of disks in use today. Leading with the highest performance at the steepest price are Solid State Disks (SSDs). Next are Serial Attached SCSI (SAS) drives, followed by the most economical Serial ATA (SATA) disks.

For random disk read patterns, SSDs are said to be 25 to 100 times faster than SAS hard disk drives (HDDs) at roughly 15 to 20 times higher cost per Gigabyte. In practice, SSDs substantially reduce the number of HDDs required for heavy random I/O pattern. Just one SSD PCI I/O card may yield the equivalent of 320 hard disk drives. That’s 300 times less hardware to house, maintain, cool, and watch over.

In general, you wouldn’t want to waste the premium-priced SSD capacity on infrequently used blocks, so the DataCore software will keep the least active information on the lowest cost, capacity-optimized SATA disks corresponding to Tier 3. On the other hand, when the auto-tiering algorithms detect sustained heavy use of certain other blocks, they will naturally bubble up to the Tier 1 SSDs.

Perhaps your diverse storage pool consists of top-shelf, premium disk arrays from one vendor, mid-range RAID subsystems from another, and relatively inexpensive racks of unintelligent disk drives (JBODs).

You define what constitutes each tier, relative to the other members of the pool. You may set up as many as 15 tiers, although 3 or 4 are usually enough to help you make good trade-offs.

As new storage products arrive on the market, the top rung could shift down to make room for an even higher performing disk technology – again, without disrupting applications.

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