There is a battle shaping up in the enterprise storage industry. On one side are those who see flash storage as an upgrade for the disk drive, and on the other are those who see it as a cache between the CPU and the drive. It’s a fundamental difference of opinion - flash chips can be used either way, and each approach has its unique benefits and drawbacks.

The Register did a nice job of summing up the (late 2008) flash positioning of the various storage companies, and I recently posted a strategic look at this core issue. Note that some, like HP and Sun (and probably IBM), seem to have an end-to-end strategy, while others are firmly in one camp or the other. In the “not yet” column, apparently, are 3PAR, BlueArc (though they offer TMS RAM), Dell/EqualLogic, HP/LeftHand.

Update: 3PAR has joined the “disk” camp. Continue Reading »

Sure, hybrid drives are going nowhere fast in enterprise storage. But what about solid state disk technology? It’s been “almost there” for decades - anyone remember EMC’s solid-state Orion Atom (or was it Adam) array?

Now a handful of storage players are talking about SSD’s again, including some respectable names like LSI and Xiotech and some lesser-known outfits like Solid Data Systems and Texas Memory Systems. IDC is predicting mainstream uptake of the technology, too, but note that they’re mostly talking about the PC market, not enterprise storage.

I say that if SSD ever gains footing in the enterprise, it’ll most likely be in a virtualized hybrid system, acting like a mega-cache. Or maybe a non-RAM permacache, if you will! Of course, we’ve seen just how much uptake that feature has had, eh EMC? But hey, it could happen. Even though Apple is soaking up more than a quarter of the world’s NAND flash this year, maybe they’ll force prices down. Or maybe Samsung’s or Hynix’s PRAM will conquer the world!

Let’s get serious, folks. What good is SSD? It improves random access read performance over disk at the expense of longevity, throughput, and, well, expense! ReadyBoost looked like a nice application for flash memory, since the potential content was bounded and could fit on a flash drive, but it seems to have done precisely nothing for performance.

If enterprise applications could benefit from better random access performance, we’d be putting large amounts of memory in front of the disks already. Oh, wait, that’s right, we already do that! Modern enterprise arrays have gobs of cache, more than any SSD, and use it quite effectively. Remember the old RAID-5 penalty?

SSD just serves to remind me of one of those performance-tuning axioms I learned long ago: It’s always better to let an intelligently-designed system manage itself than try to second-guess it. This applies to all areas of system performance tuning, from filesystem and LUN layouts to cache tuning. And this is why permacache and things like it never caught on.

And it’s why SSD will continue to play just a bit part in the enterprise until it’s just as cheap as disk. Like that’ll happen anytime soon.

Edit: Looks like I got the name wrong - the EMC SSD was the Orion.  Introduced in 1989, this evolved into the Symmetrix in 1992.  I used one of these back at Texaco in the 1990’s.

Marc Farley’s challenge of listing all the devices on our home networks got me thinking –I’ve got an awful lot of Linux devices, but all of them are infrastructure rather than interactive PCs. Of the 10 devices currently attached my home network, four are Linux based (two TiVos, a Linksys router, and Linksys NAS), three are Windows PCs (two Vista, one server 2003), and the rest run various embedded operating systems (a Roku SoundBridge, an HP printer, and a 3Com Audrey running QNX).

Notice that all of my PC’s run windows, while all of my servers run Linux! This got me wondering what role Linux plays in enterprise storage. Sure, Linux has a huge role to play on the computing side of the equation. But which enterprise storage devices are based on a Linux kernel?

Xiotech made a big splash a few years ago by announcing that they would switch from a proprietary operating system to Linux. I remember seeing Open-E’s Linux based iSCSI software somewhere, and hearing that Snap Appliance (now part Adaptec) of was using it as well. I consulted LinuxDevices.com and found out about Infrant (now part of NetGear), MaXXan (nee CipherMax), and Raidtec.

There have got to be more! So tell me, who is using Linux as their embedded kernel and why? Was it for convenience, hardware support, or perhaps a financial decision?