Learn about SAN

[PatricF]

Hi,

I work for a company which host different services like web, dns, mail and all that. I'm currently thinking about buying a SAN for out servers but I have never used a SAN before so in that area I'm kind of new.

Are there information somewhere on how SAN works and how you would deploy a SAN, setup LUN's etc. and all about how it works?

I feel that I need to educate myself in this area but can't find any clear information about the subject.
If you know any books or other literature please recommend. If there are any online information it would be even better.

We are just using HP servers and network equipment so we are thinking about buying a LeftHand P4000 series SAN, or maybe go down to a P2000 if the budget wont let us buy a P4000.

So we are pretty much talking about a more budget SAN and not something from EMC or HP's EVA or anything like that.


Any information is welcome!

Thanks,
-Patric

 

[cajuntank]

You of course will find a plethora of hardware independant information about SANs doing Google searches (what is a SAN, SAN technology basics, etc...), so that should be pretty straight foward.

On the matter of looking at the HP product, I can be a little more granular in assistance. I own both the P4000 and P2000 series product and they work very well in my opinion. I use the P4000 series product at my district office (I', a K-12 ED) and P2000 products at some of my school campuses (I will be deploying these P2000's this summer). The P4000 product series will be a more typical SAN technology product due to having a lot of software feature built in. Where the P2000 will be more limited to its functionality, but still a great entry level commercial SAN product.

I know on the P4000, it really comes down to the number of SAN nodes you deploy. You have RAID level on each node you can choose, RAID5, RAID1+0...but for the SAN to really be effective, you need multiple SAN nodes. When I say SAN nodes, that basically means multiple storage servers. So you could purchase a P4300 G2 16TB starter kit. This will consist of two P4300 G2 8TB servers that you would put into one cluster group. The individual server would be for example RAID5, so 7TB of RAW space on each box, then with both boxes being in the same cluster group, when you create volumes for your Windows/Unix/VMWare/Etc...servers, you would then choose to RAID0 or RAID1+0 the volume itself. RAID1+0'ing the volume will mirror that volume across nodes. So in this scenario, you can have a hard drive fail and your protected. You can have a whole SAN node fail and your protected. This also allows you to do maintenance on the nodes during production hours as the volumes are mirrored and while it's updating one node, the other is serving the volumes to the servers as normal, then vice versa when its done with one and ready to update the other node. The users never know there's anything going on.

The more nodes, the better you are protected and the faster the data access to the SAN is due to multiple network adapters on the SAN nodes. So best practise when implementing the HP SAN (and I'm speaking purely of this HP P4000 and P2000 product using iSCSI) is to have external redundancy as well. Two dedicated switches (I use HP Procurve 2910al switches for this), two dedicated network adapters in each of your Windows/Unix/Etc... servers. This way, each SAN node (standard config has each node with 2x1Gb NICs... there are 10Gb options) will plug into each switch, each server will plug into each switch. This way, you have multiple paths and using the HP MPIO driver (instead of using Microsoft's MPIO driver), you will have the greatest redundancy and speed access to your volumes.

Hope that wasn't info overload and if you need to know something specific, just let me know.

Hope I helped.