Thanks for all the very helpful replies. FYI, I also finally found a good link at Cisco that describes SANs in a "top-down" way, with pictures, and few acronyms. ;-)
Here it is: http://www.cisco.com/en/US/products/hw/ps4159/ps4358/products_white_paper09186a00800c4660.shtml Priscilla Steven A. Ridder wrote: > > 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=56933&t=56857 -------------------------------------------------- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
