The IBM N boxes are rebranded NetApp filers… They have some interesting features including a block optimized file storage.
I’m not up on all the different N series models however I believe the N5000 series includes both NAS (iscsi) and SAN (fibre) options where as the N3700 contains only the iscsi.
The downside to the Netapp the way I understand it is it uses dual parity raid 4. In theory this is not as fast as raid 1 for database access.
You need to consider how much storage you actually need?
1 TB, ? 100 TB, etc?
Then consider your reliability requirement. Is a single controller good enough or do you require redundant configuration.
Then look at your existing gear… Do you already have Fibre switches, or top end cisco switches?
If your going the iscsi route you must have good switches and you will pay a performance penaulty for the iSCSI overhead.You will also want to segment your storage onto a seperate vlan and seperate cards if there is a lot of disk i/o.
If you go the fibre route then you need to learn about zoning. Depending on the size of your shop you may or may not need to get deep into the high end directors.
I would also consider using the IBM DS 4000 line of storage controllers or even direct attach storage if you only need to provide storage to a few servers as being way more cost effective.
The other thing to consider is what your server architecture is. Are they diskless and will you need to san boot? Some equipment allows you to do this on a non zero lun while others require it. implying you need more storage partition licenses.
My personal feeling is stick to the fibre attachment with storage as there is less overhead and more bandwidth. Also don’t make the mistake of forgetting backup. (and with the exchange archive)
When making large storage purchases over buy as you can negotiate disk prices down a lot farther then when you need to buy a few more trays 6 months later.
As for your operational cost… You shouldn’t need an expert in TCPIP to manage either iscsi or an expert in FC. You will need someone on staff who is familiar with whatever you buy and there is no real difference. Either method provisions storage over a network and all the way through have the same concepts with different acronyms.
Once it’s setup and working there is very little day to day maintenace. Every few months I get an email about needing a disk drive from my arrays and that’s about it. Only time there is work is when you need to assign or add disk and with a little pre planning you can have your disk ready to assign almost instantly on need.
Hope that helps.