iSCSI on the Mac

On the Microsoft Windows OS, iSCSI has reached a very mature level. On Linux, the Linux-iSCSI project has a refined iSCSI initiator. On the Mac, there are only a few vendors, and most are on their first generation iSCSI protocol drivers for Mac OS X Panther 10.3 and Mac OS X Tiger 10.4 OS. This is all going to change in the next several months.

Apple Computer has a SAN solution, compatible with ADIC’s StorNext File System called xSAN, a new disk paradigm that supports Mac OS X application only. In order to use the xSAN file system, one needs to erase completely and reformat any attached drives, including RAID subsystems.

Currently xSAN is supported through fibre channel networks only, and requires a dedicated ethernet port for metadata. iSCSI allows a traditional gigabit ethernet (GbE) network to become dedicated to storage with a moderate performance decrease. One can install a dedicated single or multiple port PCI card for dedicated GbE storage networking and internet traffic.

ATTO Technologies offers the Xtend SAN and Studio Network Solutions offers the GlobalSAN product. In the near future, expect D-Link to have products ready for market that go beyond the 1 GbE connection, stretching the storage platform to 10 GbE, beyond the range of 4 Gb fibre channel.

Panasonic AG-HVX200 Camcorder History

panasonic AG-HVX200 camcorder front view

During the Panasonic CES 2004 keynote address, Andrew Nelkin, Vice President of Panasonic Consumer Electronics Company first hinted that by the first quarter of 2006, Panasonic would produce an affordable high definition camcorder using solid state flash memory devices (secure digital memory card or SD cards). The magic date became Torino 2006, the home of the next Winter Olympic Games, where Panasonic traditionally has a commanding sponsorship.

Fortunately, Panasonic did not wait until CES 2006 to announce the new products, but instead had a very large presence at NAB 2005 for the professional DVCPRO HD AG-HVX200 rollout, and IFA 2005 for the consumer MPEG-2 based camcorder rollout. Both products are expected in the fall of 2005.

Unlike traditional portable video capture devices, these new camcorders have no need for magnetic tape. Video tape has it litany of problems including jams, dropouts, snags, tape breaks, curl, and video tracking along with environmental issues like susceptibility to humidity, magnetic field erasure, and simple aging. The era of the cassette is over, and the opportunity to be creative faster and more robustly has arrived.

The first generation product, with a 2 GB to 16 GB starting storage capacity, will need a new workflow. The recording medium, a reusable SD memory device, once filled, needs to be put somewhere, and a storage area network (SAN) or RAID device would be ideal to protect the invaluable electronic image capture. As the era of solid state recording dawns, notably other backup devices are either already mature or nearly ready to archive the DV, DVCPRO HD or MPEG-2 recording.

Today, DVD+R makes an entry level archive medium, with a 4.38 GB (17.5 minutes in DV format, 11 minutes DVCPPRO HD 720p/24) storage platform. DVD+R is cheap, reliable, and long lived. On the horizon, look to Blu-Ray Disc with a capacity of about 25 GB, five times the capacity of DVD+R. Also on the cusp is holographic storage at some 300 GB a cartridge.

panasonic AG-HVX200 camcorder P2 memory slots
panasonic AG-HVX200 camcorder P2 memory slots
panasonic AG-HVX200 camcorder side view
panasonic AG-HVX200 camcorder side view

Hive Mind Grid Computing Mac

There’s been a dream of mine to have multiple cheap machines networked in a way to form a hive mind, so commands on one distribute to all and work together. This is loosely called grid computing. Imagine 3 iMac G5’s, Power Mac G5’s, or PowerBook G4’s networked together to work as one. The future is now!

At NAB 2005, Apple announced Final Cut Studio, which allows distributed Compressor rendering/encoding, so through a dedicated gigabit ethernet or firewire infrastructure, you combine a few machines into a working super computer. Mac OS X Tiger has as it’s base a technology called Xgrid, which is a protocol for clustering machines together out of the box.

The secret to success is the gigabit ethernet connection running at 1 Gbps or 128 MB/s. so now in the new computing model, the CPU comes second to the network connection. In a few years 10 gigabit will be standard, passing 2 Gbps or 4 Gbps fibre channel.

So now that you can grid the machine together, how about storage? Apple has an Xsan solution. Xsan costs just below $1500 a workstation to get the computers to share storage ($999 Xsan seat license, $499 fibre channel PCI-X card). A much more elegant and economical solution, that works on panther 10.3.5 and above is iSCSI.

you remember SCSI? all macs had it before ATA. Storage engineers never gave up on SCSI, and are reintroducing the SCSI protocols, but over gigabit ethernet! On a more modern mac, you already have the port, or can easily get a $20 network PCI card (recommended approach to separate the storage network from the IP network). The beauty of iSCSI it can be entirely software based, so yes you get a performance hit, but imagine sharing all your hard drive on a small gigabit network using software SAN. This is revolutionary. Current vendors that support the Mac are ATTO technology and Studio Network Solutions. These companies are just the beginning to a wonderful marriage of storage, grid computing, and the Mac.

apple Xserve G5 cluster nodes
apple Xserve G5 cluster nodes

Networked Storage Basics

Almost since the beginning of desktop computing, the ability to share has been essential. Flash forward 30 years, and not only are computers networked, behold the pervasiveness of the internet to every workstation and laptop, but soon every computer will have shared storage. The simplest form of sharing would be networked attached storage (NAS), where you use built in networking protocols (TCP/IP, SAMBA, NFS, AppleTalk, etc.) to mount a remote volume over the internet or over a local area network (LAN) to a client system. You can now parcel files, using the file sharing aspects of the operating system.

A more robust system in the NAS space, uses an intelligent controller, or server (Mac OS X Server, NAS head, etc.) to deliver storage connectivity.

Companies like NetApp and BlueArc have mastered the front end of the storage array, and allow on the fly configuration, modeling, and allocation of storage resources as the needs of the enterprise change. Certain applications, like databases, require block level access to storage devices, as if they were directly attached to an individual computer. Application performance may suffer if the program is looking for block level access, but only sees NAS, however, in general, NAS is fast and is a completely viable storage platform.

Be it a NAS environment or a storage area network (SAN), most likely SAN is the storage subsystem architecture anyway. Currently there are three ways to attach a SAN to a workstation or workgroup:

Fibre Channel
Gigabit Ethernet, GbE (iSCSI)
IEEE 1394a or 1394b (FireWire)

Each methodology has is benefits and pitfalls, but all offer rugged access to shared storage resources. With a shared storage solution, the workstation can boot from the SAN, share files and applications (if the software licensing agreement allows it), and make the backup and restore aspect of data management easier.