On Mon, Apr 23, 2001 at 09:50:58PM -0400, Brian Tao wrote:
On Mon, 23 Apr 2001, Gifford, Josh wrote:
I will be upgrading my filer to redundant fcals this week and I wanted to check to see if anyone is already doing this. I don't think there will be any tricks to it, but it never hurts to ask.
What benefit does this bring, beyond protecting against an FC-ALfailure on a single Netapp? Any additional benefits while in a clustering scenario?
As long as we are talking FC-AL, DMP and clustering (on NetApps) are mutually exclusive. The disk shelves still have only two ports therefore if you cluster (one port to each host), there are no ports left to have redundant paths to either host.
If I were consulting, I'd say that if you don't want to full cost of clustering, but still want some degree of "high availability", that DMP is useful. Especially on big FC-AL loops with lots of devices, one node (disk or host) can really hold the entire loop hostage and wedge the filer. In this scenario, DMP just switches all drive communications over to the functioning path.
I'm sure there would be disagreement on this, but it may pose a slight performance increase because it appears to load-balance across the redundant HBA's if neither is failed out. Whether this is true or not, that performance probably never gets realized at the client's side due to the fact that filers aren't usually disk bound anyhow.
Oh, and I'd like to put a motion on the floor that Sam's posting authority to toasters be fully re-instated. =)
-- Jeff
-- ---------------------------------------------------------------------------- Jeff Krueger, NetApp CA E-Mail: jeff@qualcomm.com Senior Engineer Phone: 858-651-6709 NetApp Filers / UNIX Infrastructure Fax: 858-651-6627 QUALCOMM, Inc. IT Engineering Web: www.qualcomm.com