Flash DIMMs hit server market

Flash DIMMs hit server market

Summary: What would you do with 12TB of server main memory? IBM will let you find out with their new eXFlash DIMM.

TOPICS: Storage, Hardware, IBM

SanDisk announced this morning that IBM is offering the SanDisk ULLtraDIMMs (developed with Diablo Technologies) on enterprise servers. The ULLtraDIMMs (silly name, eh?) are a mix of DRAM and flash memory.

Since flash is cheaper than DRAM a server can be configured with much less DRAM and much more flash for a much lower cost. SanDisk says that twice the performance can be had for less than half the cost.

IBM's application example is virtual desktop consolidation where 10,000 virtual machines are being deployed. With 700 GB of PCIe SLC flash storage and 384GB of DRAM a physical server can support 100 virtual machines.

With four 400GB MLC ULLtraDIMMs and 64 GB of RAM the server can support 200 virtual machines at less than half the cost. But as of yet there is no more detailed pricing info. Config info is sparse as well.

IBM is branding the SanDisk product as eXFlash DIMM. They say that it has a 5 to 10 µs rates latency and that their servers can support up to 12.8 TB of them.

Storage Bits was briefed on the product by Diablo last August. Read more about the technology here.

The Storage Bits take
The ability of servers to access terabytes of main memory is a game changer for the industry. Instead of putting databases on hard drives or even PCIe flash drives, those databases can be placed in main memory for maximum performance.

However, databases have long been engineered to minimize the latency of standard hard drives. But all their caching and look-ahead tricks get in the way with fast storage. Thus the emergence of specialized in-memory databases.

The acceptance of th technology by IBM will accelerate the uptake of this exciting new technology. If you were hoping for a slowing storage rate of change it looks like you'll have to keep waiting.

Comments welcome, as always. What would you do with 12 TB of main memory on your PC? Server?

Topics: Storage, Hardware, IBM

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  • But in a server environment, how many writes before the Flash DIMMS


    This could be "RAMBUS II" in the making...

    It's a clever idea, but in practice...
    • SLC Flash is much more resilient than typical consumer MLC Flash

  • swap by another other name

    Even at 5 microseconds the NV pool latency still feels too high for memory access semantics. As such , accessing this extended NV memory space still feels like an IO process to me.

    The notion of a greatly improved swap device could have merit in some application but if I want to keep application performance high, I wouldn't start dialing down the amount of working memory I keep in play just yet.
  • Hot swappable?

    If it's not hot swappable, it won't be server ready no matter how much PR spin is put on it.