SAN design

[Ammad]

HI,

i am new to SAN. i have 5 MSA storage devices.

MSA 1000
MSA 1000
MSA 2000
MSA 2000
MSA P2000

I am going to use P2000 as Backup to Disk. Right now all storage devices are connected to directly to Servers.

There was no SAN switch and inter connectivity between storage.

since I am going to install Backup software, that will backup all hosts to disk and then to tape.

I purchased SAN backup license, to directly backup data from storage to backup disks (P-2000).


I want to know the considerations and guide to design SAN.

may be LUN conflict occur if i connect all storage to SAN switch or all volumes visible to other hosts.

Your assistance will help me to have proper design.

[Jags_21]

Hi Ammad,

first thing I would suggest is not put all SAN box on one SAN switch, though it is possible with the help of zoning (which will mask the ports were servers can see only the luns to a speific storage) and again you need to go for an SAN switch which has more ports based on number of servers you want to connect (these switchs involve more cost), in case there is issue your entry infarstructure will be in a trouble.

Go with multiple san switch with inter-link san switch option and configure zoning so that it does not conflict

Also I would suggest to get touch with HP pre-sales team they should help you in getting the design

[Don Mallory]

HP has a their "SAN Design Reference Guide". You can find it on the SPOCK site:

http://h20272.www2.hp.com/

That said, it doesn't tend to give the best of advice on all points.

The biggest contention I've always seen is that it recommends putting multiple devices in the same fabric zone. The industry best practice is single target-single initator zoning (one target, one initiator in the same zone), which limits the effect of fabric broadcasts, scsi resets, etc (especially for tape or virtual tape devices).

As a minimum, a redundanct switch fabric (two switches), plus well managed zoning is required. Additionally, zoning will not help with LUN masking, those are two different things, and you may want to control the device / LUN presentation (which host sees which LUNs) at the array level more than just these.

I am not familiar witht he P2000 and it's SAN backup license, but unless it's some form of application aware online synchronous replication of data, or app aware asynchronous replication of snapshots, the recoverability of the data will be in question. Example: exchange databases. Your data is on the source, you snap and send it to a destination, yay, it went fast.. but exchange wasn't aware that you created the snapshot, so, when you recover, you end up in a failure mode at the recovery site and for some reason the data happened to be in a bad state at that time (which is any time that the database has not been quiessed), and oops, no successful recovery possible.

I agree. You should probably contact your HP pre-sales rep about some consulting services.

Best regards,
Don