StorageMojo

Spent an hour talking to Mark Stratton, a VP of startup Crosswalk, about their new product, the iGrid 5100 Intelligent Storage Grid series. So what is an iGrid and why should you care? Initially, Crosswalk is aiming at the HPC market, yet longer term they have designs on the higher-end NAS market. They may have the industry’s first scalable NAS solution, good news for every large user of NAS.

What iGrid Does
Crosswalk’s new system provides a NAS (NFS, CIFS) front end to standard storage arrays. The front end is a cluster, so it scales horizontally, while also providing cluster levels of availability, redundancy and performance.

Each of the cluster nodes presents the entire capacity of the backing storage to the servers, so it doesn’t matter which node a server deals with. The nodes create file systems to present to the servers, virtualizing the backing storage. Crosswalk’s software handles the back end volume management, provides snapshots and interfaces to NetVault’s VDL software for backup. Since it is a cluster a single node can back up the entire storage pool.

There is no Crosswalk server-side software.

iGrid Architecture
When I spoke to Mark I was mostly interested in the architecture of the product. I spent several years at YottaYotta, which also built a clustered RAID controller with a network backplane, so I have some experience in this area.

Each cluster node is a 3U box with up to 8 front side gigabit ethernet ports and up to 8 backside 2 Gb FC ports. Each node is a quad-processor with 16 GB of cache, expandable to 32 GB. There are also multiple gigabit ethernet ports for inter-node communication. Some might question the use of gig-E as the cluster interconnect, but in my experience passing metadata, addresses and lock management just aren’t that taxing. There is no custom silicon.

They currently support an eight node cluster with plans to increase that number to 256 over time. They also plan to offer block services as well, with iSCSI support.

The nodes expect nothing more than mid-range active-active Fibre Channel RAID arrays on the back end. Thanks to the cache-heavy nodes, Crosswalk believes they can get great performance from RAID 5.

iGrid Management
The iGrid admin sees all the backside LUNs and collects them into volumes upon which Crosswalk’s software places filesystems. New file system creation is quick - as fast as you can click through the GUI. There are some preference setting options to simplify setting up new file systems and adding arrays to the storage pool. There is more than I’m relaying here, but these are the basics.

iGrid Futures
In addition to scaling up to 256 nodes and block services, Crosswalk has some other intriguing possibilities. Since their product is software based, they could use much lower cost servers to drive their entry pricing down, while expansion to 256 nodes would preserve their growth path. They could also lose the back end FC, in favor of iSCSI or SSA, further driving our cost and increasing flexibility. Since their internode communication is over standard gig-E, they could also geographically disperse their nodes over a MAN and tap the high-availability market. They might also port a (future) cluster-aware ZFS and allow customers to lose the expensive and latency inducing RAID controller layer altogether.

The StorageMojo take
Crosswalk, founded by Jack McDonnell, who had good success with McData, with CTO Raju Bopardikar, formerly of ill-fated Cereva, certainly has the bones for success. They’ve done a number of important things right: no host software; no custom silicon; commodity hardware; partnering where possible; horizontal scaling. This puts them ahead of getting-long-in-the-tooth startup BlueArc.

The High Performance Computing (HPC) focus is questionable. My experience is that folks who start with HPC stay there, because each HPC customer has so many interesting requirements that engineers love to solve and that will never make a dime for the company. Performance-driven customers ask for all kinds of enhancements that most commercial customers will never notice. So I wish them luck expanding past that market.

Another concern: the Denver location. STK culture - mainframe, big iron, slow to adapt - looms so large in storage circles there that there really haven’t been many successful storage startups. Jack overcame that at McData, although you might recall that McData sold mainframe ESCON directors to IBM for years before getting into, and largely outmaneuvered in, the Fibre Channel market. Does Crosswalk really want to go after the big NetApp and EMC NAS boxes?

Crosswalk has the potential to upset the current NAS players. Yet I think they’ll need a stronger cost argument in addition to cool technology. Fortunately their architecture gives them lots of options. I wish them luck.