To hear this week’s storage industry news reports, one might think that Wagner’s fat lady came to Storage Networking World (SNW), singing her song as the iSCSI world collapses. Storagebod wonders what iSCSI’s death will look like. Chris Mellor at The Register says “Game Over” as NetApp, QLogic, Emulex and VMware join EMC and Cisco in singing the praises of Fibre Channel over Ethernet (FCoE). Mellor suggests that the protocol will devalue Dell’s EqualLogic investment, as if HP’s acquisition of LeftHand wasn’t enough, even as fellow Register-ite, Bryan Betts disagrees.
But The Register didn’t invent the “FCoE kills iSCSI” meme – it’s just natural to imagine that these two protocols would be in a fight to the death. And if it’s a duel, then this year’s SNW conference would seem to be the first volley, as EMC introduced a FCoE Connectrix switch (based on Cisco), NetApp announced the first native FCoE array, and everyone qualified Emulex and QLogic adapters. However, despite these announcements, it’s way too early to bury iSCSI!
FCoE and iSCSI are similar in concept:
- Both rely on Ethernet physical connectivity
- Both transmit SCSI packets
- Both are aimed at date center users
But there are major differences as well:
- iSCSI is routable in an IP network
- iSCSI can use IP services like IPsec
- Software initiators can give iSCSI connectivity to any server, regardless of hardware
- FCoE will require converged network adapters (CNAs), while iSCSI can run on any Ethernet adapter
- FCoE will start at 10 Gb, while iSCSI can operate at just about any speed
Looking at this list, one might realize that FCoE is really a competitor for faster-than-4 Gb Fibre Channel. It’s not just a data center product, it’s an enterprise (read high-end and expensive) product, and that’s exactly where it will flourish. I have no doubt that Cisco and Brocade will successfully transition their Fibre Channel product lines to FCoE, and that QLogic and Emulex will sell a gazillion CNAs. But what about the rest of the market?
VMware’s adoption has shown that there is a taste for shared, networked storage outside the rarified budgets of the enterprise world. So far, no storage protocol has won the midrange and virtual server market, with Fibre Channel, iSCSI, and NFS duking it out along side internal SAS and SATA and the odd InfiniBand and external SAS solution. Although CNAs and FCoE ought to work fine in the virtual data center, not everyone will have a taste for them. There will always be plenty of folks who just want inexpensive external networked storage arrays, and iSCSI is the best thing they’re likely to see any time soon!
And iSCSI isn’t done evolving. Folks like Mellor, Chuck Hollis, and Storagebod are lauding FCoE at 10 gigabit speeds, but seem to forget that iSCSI can run at that speed, too. It can also run on the same CNAs and enterprise switches. And although wide(r)-area SANs aren’t common, I’m beginning to see some interest in leveraging the routability and other advanced features of IP in the storage world. iSCSI still has some cards to play! And the non-enterprise space isn’t nearly as awful as some make it sound – it is and will remain a bigger, more diverse market than the high end, and there are some serious buyers that will never get into FCoE.
Right now, the SAN world is expanding like it hasn’t done for years. iSCSI deployments are accelerating, growing the whole market. Sure, FCoE will probably completely replace old-school Fibre Channel over the next five years. But it will have to share the market with the now well-established iSCSI. It looks to me like Dell and HP made smart investments.
Update: More coverage on the topic:
- Doug Rainbolt from Alacritech is skeptical of the drivers for FCoE
- David Dale from NetApp feels that FCoE is unlikely to intrude on the iSCSI “sweet spot”