topic Windows FCP and need for DSM and Snapdrive in Data Protection

Windows FCP and need for DSM and Snapdrive

animesh129 — Thu, 05 Jun 2025 07:27:30 GMT

Hi,

In a scenario where we need to connect multiple Windows Servers with 2 HBA's each to a Netapp FAS3140 using FCP and 2 redundant SAN switches:

1. Is Snapdrive mandatory?

2. Is DSM mandatory?

3. Would it work with neither of these and use Host level Multipathing ( MPIO) with just FCP enabled on the FAS?

( This is a test environment and the benefits of snapdrive are not necessarily needed at this point)

Thanks

Re: Windows FCP and need for DSM and Snapdrive

radek_kubka — Thu, 11 Jun 2009 20:15:43 GMT

SnapDrive is optional.

DSM is required for multipathing, so without it you are limited to a single FC connection (which may be OK in test environment)

Regards,

Radek

Re: Windows FCP and need for DSM and Snapdrive

erick_moore — Thu, 11 Jun 2009 20:40:27 GMT

Neither is required, but it is best practice to install the NetApp Host Attach kits. This will install the DSM software and set your HBA's, and Windows registry settings to the proper values to support failover. The host attach kits are free so there is really no reason NOT to install them.

Thanks,

E-

Re: Windows FCP and need for DSM and Snapdrive

radek_kubka — Fri, 12 Jun 2009 11:11:44 GMT

Erick,

Are you sure you can do FC multipathing without DSM?

This is what NOW pages say:

The Data ONTAP® DSM for Windows® MPIO is a device specific module (DSM) that works with the Microsoft Windows MPIO drivers (mpdev.sys, mpio.sys, and mpspfltr.sys) to manage multiple paths between NetApp and IBM N series storage systems and Windows host computers. The DSM includes the storage-system-specific intelligence needed to correctly identify paths and to manage path failure and recovery.

http://now.netapp.com/NOW/knowledge/docs/mpio/win/reldsm32r1/html/software/install/concept2.htm#1159068

Regards,

Radek

Re: Windows FCP and need for DSM and Snapdrive

erick_moore — Fri, 12 Jun 2009 12:00:19 GMT

The host attache kits actually include the DSM software. Again, even in a test scenario there is no reason to not install these. I have generally found you always want your test environment to be as near production as possible anyway.

Re: Windows FCP and need for DSM and Snapdrive

amiller_1 — Sun, 14 Jun 2009 04:34:02 GMT

Just to elaborate a bit, the Host Utilities (HU) should always be installed -- DSM is actually optional (as there is an MS one) but but needed for a cluster setup to correctly distinguish between primary/preferred and secondary/partner paths.

In short, install HU & DSM and you'll be fine (SnapDrive as well if you want to).

Re: Windows FCP and need for DSM and Snapdrive

jooss — Wed, 15 Jul 2009 16:40:41 GMT

The DSM is not included as part of the host utilities.

If you have an active/active system with connections to both controllers you'll have mulitple paths to the LUN even if you only have a single path in the host (assuming the host can access both controllers).

With the HU and DSM I'll bet all will be well.

Re: Windows FCP and need for DSM and Snapdrive

javed — Wed, 15 Jul 2009 17:18:06 GMT

To install the Netapp DSm you need to have the license for it . im not sure whether it comes free or you have to buy the license. But as per netapp best [practice for fc luns on windows Netapp dsm is preferred over microsoft dsm. I have faced issues with microsoft dsm whith fc path misconfigured errors .but once i installed the Netapp dsm the errors did not appear again

Re: Windows FCP and need for DSM and Snapdrive

amiller_1 — Thu, 16 Jul 2009 13:17:15 GMT

Not sure if I'm repeating but.....

For FC you really want the NetApp DSM (as it knows about the partner connection between cluster controllers and can optimize the paths for that).
For iSCSI (albeit not your question) the free Windows MPIO is just fine.