topic Re: nvram usage in ONTAP Hardware

nvram usage

hongwei — Thu, 05 Jun 2025 07:00:19 GMT

Hi guys,

I understand that nvram performs mirroring in a clustered environment whereby 50% of the nvram will be used for write and 50% used for mirroring.

Say in a FAS2040, i would only be using 256MB for writing right ?

But how would the usage be if it is in a single controller ?

Would i be able to use all 512MB for writing or will it still be reserve by the system for mirror etc ?

Regards,

HongWee

ekashpureff — Fri, 11 Feb 2011 01:22:47 GMT

In a single head environment all of NVram is utilized to log write operations.

NVRAM is split into two pages - p0 and p1.

In an HA Pair the NVRAM on each member is split, and all writes are logged

on the local and partner NVRAM, for both p0 and p1.

NVRAM is good for about three days. I've got a real interesting story about

NVRAM and cluster failover involving hurrican Ike, but maybe I'll save that

story for later.

I hope this response has been helpful to you.

At your service,

Eugene E. Kashpureff
ekashp@kashpureff.org
Senior Systems Architect / NetApp Certified Instructor
http://www.linkedin.com/in/eugenekashpureff

(P.S. I appreciate points for helpful or correct answers.)

hongwei — Fri, 11 Feb 2011 06:48:08 GMT

That was really helpful ! thanks alot !