Web Hosting Talk : Web Hosting Main Forums : Hosting Security and Technology : iSCSI SAN or FC SAN

[prashant1979]

Which one is better? iSCSI SAN or FC SAN? Should I build my own or buy one?

[snoms]

Hi,

I did have similar questions:
http://www.webhostingtalk.com/showthread.php?t=1055515

To make it short, take iSCSI...

[MikeTrike]

iSCSI is easier to setup and manage vs. Fibre Channel, but naturally does not have the capacity that FC does. Granted if you do your own custom servers/array's you can use 10GbE fiber ethernet for iSCSI. You also need to worry about the number of licensed FC ports you have on your FC switches, which are also pricey. In most cases GbE copper ethernet for iSCSI will get the job done, unless you're pushing massive amounts of data on really heavy load applications. At the office we run a Dell AX150i and Dell MD3000i, both being iSCSI and they run great. The MD has SAS and the AX is SATA, we can put quite a bit of load across the iSCSI without issue.

So if you need easy to manage, easy to deploy, cost effective; go iSCSI. If you need the absolute maximum performance, the knowhow to use FC, and cost is of no concern; then you might consider FC.

[wartungsfenster]

Originally Posted by snoms

Hi,

I did have similar questions:
http://www.webhostingtalk.com/showthread.php?t=1055515

To make it short, take iSCSI...

I think FCoe vs. iSCSI is a totally different thing than FC vs. iSCSI.
FCoE is a still rarely deployed tech that has low reliability compared to FC because it depends on (datacenter) ethernet.

There's a reason why there's virtually no large-scale SANs based on iscsi, i.e. that iSCSI management is a lot more complicated once you actually set it up to include security and have reasonable reliability. And it will *never* be lossless.

[snoms]

Originally Posted by wartungsfenster

There's a reason why there's virtually no large-scale SANs based on iscsi, i.e. that iSCSI management is a lot more complicated"

As I am still looking around about that topic, I´m intersted in those reasons. Why is iSCSI management more complicated than that of FC? According to vmware, I can easily use both.

[OffshoreRacks]

FC is way more complicated and messy, for a start its limited to 1 Gbit - 2Gbit in most cases, you need special FC cards on each server, FC switch and the cabling you can't find everywhere, also is a dying market.

IScsi, you can use your actual cabling, switches (they need to support jumbo-frames, layer2, Gbit), you can use actual 1 Gbit ether cards on server, and on the future you can increase to 10 Gbit switch and cards.

If you are thinking about FC is because you have the money go ahead and get ISCSI solution at 10 Gbit for a start, is almost the same as FC switch and cards and they can reach +1000 MB/s disk throughput.

I have 2 EMC FC SANs as paper weights.

[MikeTrike]

Originally Posted by snoms

As I am still looking around about that topic, I´m intersted in those reasons. Why is iSCSI management more complicated than that of FC? According to vmware, I can easily use both.

Same, I've used both iSCSI and FC... Granted, I don't do anything large scale; iSCSI has never given me any trouble on commodity hardware and more expensive hardware alike.

[wartungsfenster]

Originally Posted by OffshoreRacks

FC is way more complicated and messy, for a start its limited to 1 Gbit - 2Gbit in most cases, you need special FC cards on each server, FC switch and the cabling you can't find everywhere, also is a dying market.

IScsi, you can use your actual cabling, switches (they need to support jumbo-frames, layer2, Gbit), you can use actual 1 Gbit ether cards on server, and on the future you can increase to 10 Gbit switch and cards.

If you are thinking about FC is because you have the money go ahead and get ISCSI solution at 10 Gbit for a start, is almost the same as FC switch and cards and they can reach +1000 MB/s disk throughput.

I have 2 EMC FC SANs as paper weights.

1/2 Gbit FC hardware is from the 90es or early 2002.
So yes

10 Year old FC is really getting a bit slow.

[MikeTrike]

Originally Posted by wartungsfenster

1/2 Gbit FC hardware is from the 90es or early 2002.
So yes

10 Year old FC is really getting a bit slow.

Yeah, even our entry FAS2020 has 4/2/1Gb/s ports. I'd say 8/4Gb would be more common these days.

[wartungsfenster]

Originally Posted by snoms

As I am still looking around about that topic, I´m intersted in those reasons. Why is iSCSI management more complicated than that of FC? According to vmware, I can easily use both.

it's very easy as long as you don't implement security or access control.
I.e. you can have lun masking very easily but most people don't evne use that with iSCSI, much less they use authentication although it's possible.

So that's why it's easy.

Once you want to build something that might not be easy right away with FC, you'll be in hell with iSCSI.
I.e. multivendor storage hardware and then you want to control which of a number of hosts sees what.
If i just login to a different storage array from my (not existing hehe) hacked box, then what stops me? in theory, there's a few mechanisms, but nothing comparable to zoning, and in practice they're hardly used.
You can build a massive amount of vlans to emulate zoning, but it'd be a) manual b) less flexible ...

So iSCSI is about the FC-AL loop that everyone stopped using IMHO.

It'd need some control plane that can do the "AAA" for storage access. Maybe this will come with flow-based switches like openvswitch, or maybe the LAN-switch & iSCSI vendors come up with something together.

[Jeremy]

It comes down to cost. FC switch vs a run of the mill gig switch. Then factor in gbic, fiber it self, oh and the fiber channel cards... If you buy a cisco fc switch you need to buy the license to enable the ports etc etc... Its Expensive....

Over all performance is 'better' with fc on a large scale.

At work I run iSCSI with 40 vmware view desktops, ad, exchange, sharepoint, sql and about 30 vms handling all kinds of tasks. This is on 3 dell sans and 4 servers (r610s)

At my last job working with fc wasnt hard to manage as they had netapp storage and the gui was a breeze only issue I had was the fiber it self. Our datacenter was to say messy and fiber got smashed a few times by the other techs and random luns would drop. Getting storage to a server was more of a pain since adding a fc nic meant downtime not good for exchange... Most servers have a spare ethenet nic etc etc.

I would pick iSCSI.


What project are you working on getting the specs of what your doing would be better to give a better response.