February 10, 2012

EMC VFCache (aka “Project Lightning”) Is One Small Step, But an Important One

VFCache is a filter driver that caches writes

EMC VFCache (née Project Lightning) is a fairly simple offering: A server-based PCIe flash card that acts as a read cache with no integration with storage arrays or hypervisors. But EMC’s entrance into the host-based flash storage market is a powerful demonstration of the wave of disruption caused by flash-based storage and high-performance computing.

The Four Horsemen of Storage System Performance: I/O As a Chain of Bottlenecks

We continually shift between parallel and serial I/O paradigms

It is tempting to think of storage as a game of hard disk drives, and consider only The Rule of Spindles. But RAM cache can compensate for the mechanical limitations of hard disk drives, and Moore’s Law continues to allow for ever-greater RAM-based storage, including cache, DRAM, and flash. But storage does not exist in a vacuum. All that data must go somewhere, and this is the job of the I/O channel.

The Four Horsemen of Storage System Performance: Never Enough Cache

Write-Through Cache

Perhaps the previous discussion of spindles left you exhausted, imagining a spindly-legged centipede of a storage system, trying and failing to run on stilts. The Rule of Spindles would be the end of the story were it not for the second horseman: Cache. He stands in front of the spindles, quickly dispatching requests using solid state memory rather than spinning disks. Cache also acts as a buffer, allowing writes to queue up without forcing the requesters to wait in line.

Hybrid SSD/Hard Disk Drives: This Time For Sure!

Hybrid can

Hard disk drive makers are adding flash storage to their conventional spinning-platter drives to improve performance and are targeting the performance PC market. Wait a second, haven’t we seen this before? As Rocky eventually said to Bullwinkle, “but that trick never works!”

Ramdisks: Back From the Brink of Extinction

System RAM is not typically used for storage anymore

Using system memory for storage is something of a lost art these days. But many of today’s I/O intensive tasks can still benefit from the untouchable quickness provided by a ramdisk. Happily, most operating systems are still capable of creating and using ramdisks.

Of Emulated Fibre Channel, Virtualization, And The Right Tool For The Job

EMC’s Chuck Hollis is one smart guy, and a very verbose blogger. As usual, he sparked a bit of a storm recently when comparing unified storage on EMC’s Celerra NX4 to NetApp’s multiprotocol FAS2020 filer. But it was one phrase in particular that got the attention of Alex McDonald and Kostadis Russos of NetApp, Martin/Storagebod, and Tony [...]