topic Re: Secure path-Load balance in Operating System - Linux

Secure path-Load balance

MGH — Mon, 24 Apr 2006 08:42:06 GMT

Hi,
I have one host server(linux ent3)with dual HBA and secure path 3.0c and enabled load balanced feature,this host is connected to EVA 5000, By running spmgr display I got 4 pathes,1-active;2-available;3-standby;4-standby,

My question is I expected I should see Two active pathes and Two Standby pathes sience i am enabling the load balance featue in SP,

Please correct me if i am wrong,

Taken in consideration the EVA LUN set as Controller A perffered path fail over.

Re: Secure path-Load balance

Darrin St. Amant — Tue, 25 Apr 2006 15:23:54 GMT

Hi,
how many luns do you have setup? If one then your not going to see two active paths considering a LUN is only online/serviced w/ one controller/port at any given time w/ EVA.

Re: Secure path-Load balance

MGH — Tue, 25 Apr 2006 23:26:46 GMT

Thanks for you reply,
yes it is one, but if I should see one active path only, then what is the function of load balance enable, and how I can utilize the second HBA for accessing the same Lun.

Re: Secure path-Load balance

Darrin St. Amant — Wed, 26 Apr 2006 08:37:02 GMT

You have to remember that EVA5000 is not an Active/Active storage array, its A/P. at any given time a LUN is online w/ one controller/port. SecurePath is kinda ambiguitious in the since that it does give you two physical active paths to the LUN but one is always in standby for failover purposes. NOT in Active/Active manner. Now if you set up another LUN then you can run another active path to this LUN accessing both path's in parity, but once again you want to make sure that LUN is online to other controller and not going through the same controller as the first. Meaning you want to LB from the EVA side too. You should read the SP install guide to get a better understanding of SP and what exactly its doing. Look at below how SP is described in the install guide.

Note: HP StorageWorks SP is a server-based software product that enhances HP StorageWorks RAID array storage systems by providing automatic recovery of data from server-to-storage system connection failuers. SP supports multiple I/O paths between host and storage, which improves overall data availability. If any component in a path between host/storage fails. SP redirects pending and subsequent I/O requests to an alternate path.

Re: Secure path-Load balance

Eric Singer — Thu, 27 Apr 2006 10:05:18 GMT

When we initially purchased our HP Linux servers we also purchased securepath for them, but later discovered that the Qlogic driver gave us the same functionaility as secure path, so we returned securepath to HP.

I'm under the impression that the new VCS 4 will turn the EVA5000 into Active/Active, however last I heard they were still ironing out problems with it.