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iSCSI Specification Approved
nasorsan writes "The iSCSI protocol is a means to transport SCSI commands and data using TCP/IP packets. This ratification by the IETF is "the last major hurdle for iSCSI to become widely supported. . . 'Now that it's done, Microsoft Corp. and Novell Inc. will release drivers, and the games will begin,' says Steve Duplessie, senior analyst at Enterprise Storage Group Inc. 'Anyone who doesn't think this is the beginning of a huge market is insane.'" he added."
iSCSI will be an important leap into the future of technology!!!!1
I mean, seriously! Who gives a rat's buttocks about low latency and high performance and sanity? I mean seriously? Who cares about the praciticality and usefulness and overall sanity?
I mean, Jesus Tap-dancing Christ. Jump on the bandwagon already! It's all about eInternet now. iTCP/IP. eHTTP. eE-mail. Who cares about design grounded in reality anymore? These days, it's all about XML and TCP/IP and Web Services? Jump on the BANDWAGON! Everything should be implemented in XML: it's a rule! The SCSI protocol is hopelessly outdated, since it doesn't use the latest advancements in XML, TCP/IP, ADO.NET, ASP.NET, SOAP and web services.
I mean, you've GOT TO BE INSANE if you aren't smart enough to get in with the technology!
iSCSI will be used in a SAN environment. This is only between computers and storage devices, and not betwen computers and the outside world. I think you're confusing SAN with LAN.
It's like how SCSI is set up today on a single computer: there's really no way to get access to the SCSI bus without first gaining access to the host computer. The LAN and the SCSI bus are two entirely different things, separated by the host computer.
When iSCSI is used, this separation should be preserved. The network that is set up for iSCSI, your SAN, should be kept separate from your main LAN. Think of it as a private network that is visible only from your file servers that have a need to access storage devices directly.
Think of a SAN as equivalent to your IDE or SCSI cable. A SAN network typically uses a block-based protocol, that will read and write individual disk sectors without regards to filesystems, access control, and so on. This is designed for maximum speed, not security. It is the job of the file server to translate this into file-based access for outside clients, and enforce the appropriate file permissions.
And yes, you should definitely have good security on your file servers....
Dr. Demento On The 'Net!
More accurately you'll see SCSI RAID arrays with Ethernet ports. The technology will initially be too expensive to put on individual disks.
iSCSI is really targetted to replace (or augment) Fibre Channel (basically SCSI over fiber optics with 1-2 Gbit data rates). Fibre Channel is very expensive both for the interface cards and for the switches. iSCSI lets everyone leverage the developments of generic ethernet switches, routers, tunnels and bridges rather than having to develop new Fibre Channel ones from scratch.
As to your second question, You could potentially plug all of the disks (or arrays) into an ethernet switch and use them individually, but it's more likely you'd put some kind of front end in place to handle the filesystem tasks. Most filesystems assume they have sole ownership of the disks and can't share partitions between multiple live nodes. You would still gain the ability to partition big disks into smaller chunks per-compute node if you connected the disks directly (and maybe some failover capability) but that would probably be offset by the inability to share data.
I think that SGI's XFS filesystem can share partitions between multiple compute nodes but I don't know if that feature made it into the Linux port. For more info on this kind of thing google "clustered filesystems".
Here are some answers/clarifycations on some stuff I've already seen in the coments here:
iSCSI is a SAN (Storage Area Network) replacement. It is not a file shareing system like Samba or NFS. The primary advantage of iSCSI over something like Fiber Channel is cost. You can build an iSCSI system with regular Ethernet switches where as Fiber Channel requires "special" switches and cableing. I would think that two systems could use the same iSCSI target, but only where it would make sense and where the file system could handle such access.
Yes, there are already are adapters. (Not quite sure how they are out ahead of the spec, but why would you let a little thing like that slow you down). They connect to the Ethernet switch (usually a gigabit switch) and therefor could boot off a volume via iSCSI.
Cisco also makes a device that can bridge lagacy SAN networks to iSCSI
[End of diatribe. We now return you to your regularly scheduled programming...] - Larry Wall in Configure from the perl