We in the Cisco world are just entering the SAN arena, but it isn't new technology. The only new thing will be iSCSI. My company is HP and EMC's largest reseller, so we have been doing this stuff for a while, but it's brand new to me. I have been picking everyone's brains the past few months to understand what all the hubbub is about in the SAN arena. Here is what I have learned so far.
The obvious: First off you need a "off disk" place to store the data should the HD fail. In the beginning there was the tape drive, usually connected to the same SCSI bus as the hard drives of the server. Since everything was SCSI, and local to the server, it was quick and speedy, and you didn't have to worry about disc timeouts, LUN addressing, or distance etc.. The limitation was obviously the challenge of managing potentially hundreds of tape drives. So someone came out with the idea of creating a large disc system that many servers could connect to via SCSI. This offered a more centralized solution for locally connected servers, but if a large company had many clusters of servers over a large city, state, country, continent and so on, this solution couldn't meet that need since the servers still connected to the central disc system via a SCSI bus. What was needed was a way to transport data over a network. At those times, 10/100 Ethernet was not fast enough, both because of the 100MB limitation (VS the GB speeds of a local SCSI bus) and the MTU of Ethernet. If I tried to transfer even a 512 byte chunk of data from a SCSI HD to another over Ethernet, the HD would timeout and give errors. I think this is where FC came in, with initial speeds of 1 GB and a direct encapsulation of raw SCSI data, eliminating the timeout issues and the MTU size, as a raw file could be large than 1500 bytes. The FC spec also offered a way to address LUN's on servers. The only problem I can find with FC is that there is no standardization as each FC switch vendor offers it's own flavor of FC, which in turn needs it's own approved FC cards for the server and each vendor of server/disc system needs to approve it's use. The next step is iSCSI, which will offer vendor interoperability and eliminate the separation of IP and FC networks. On the LAN end, Cisco is going after Brocade with a new Switch in the 9xxx family (can't remember the exact name) that, from a technical issue, beats any Brocade switch hands down (now if only the EMC's, HP's, Hitachi's and IBM's would certify it). The 9xxx has 128 ports on 1 bus, vs a large brocade that has 32 ports over 2 busses, for a total of 64. Not only that, the 9xxx switch looks like a Cat 6k, and therefore is modular, and can combine FC/IP/iSCSI all in 1 box. Cisco hasn't come up with a "go-to-market" strategy yet, but I have met with one of the Technical Product Managers at Cisco, and it's coming any day now, so expect to see Cisco go head to head with Brocade. That may tackle one issue, but I have other needs where I need Cisco today: Now the big thing is DR, where I can back up data over WAN's to a remote DR site. The problems I am encountering now is two fold: I can't use a Cisco WAN router to take FC on LAN end and send over WAN such as a T1 or T3. I have customers doing AVVID and storage, but it's over IP, and not FC or iSCSI. Cisco is off on the right foot with AVVID, but it needs an "S" at the end (S is for storage). Once I can combine all 4, (from what I can gather, storage is just another application with it's own needs- *CAN* use a ton of bandwidth and is latency sensitive like SNA or Video) I can tell large, LARGE enterprises that we have a great DR solution. I don't think that SAN's are for most companies, just the large ones. The other problem I have is that none of the Cisco gear is certified, and it doesn't matter how awesome Cisco's gear is, if the vendors won't certify it, then they will fail. If I had to add a third problem, I'd say iSCSI hasn't lived up to it's hype yet, and there are very few products (servers and disc systems) out there that offer native iSCSI. I am not a SAN expert, but I have seen more companies willing to invest in a SAN than a IP Tel network, so it's a good thing to learn, but not today. ""Priscilla Oppenheimer"" wrote in message news:200211050001.AAA21659@;groupstudy.com... > Is anyone using Storage Area Networking? How do you use it? How well does it > work? What problems does it solve for you? > > It it really networking, the way we know the term?? It sounds like it's sort > of the next generation of file servers, but it also sounds like it's just a > new way of managing hard drives. > > I'm having a difficult time figuring out what it is really. Thanks for > helping me understand it. > > _______________________________ > > Priscilla Oppenheimer > www.troubleshootingnetworks.com > www.priscilla.com Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=56871&t=56857 -------------------------------------------------- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
