LIF migrations will only be NDO in SMB2 and 3 if the client has established a durable handle. But SMB1 clients will always have a disruption. One way to build in additional resiliency to CIFS is to use LACP ifgrps to eliminate port failure as a potential NDO issue.

Luckily, only Windows XP and prior default to SMB1. Win2k8 and beyond use SMB2 or later by default. The NDO capability depends on client, SMB version, etc.

SFO/CFO scenarios will always have a disruption unless you use SMB3 CA Shares, which currently have limited use cases.

From: Milazzo Giacomo [mailto:G.Milazzo@sinergy.it]
Sent: Wednesday, July 29, 2015 11:06 AM
To: Parisi, Justin
Cc: Toasters; Basil
Subject: R: NDO & CIFS

Yes, I know that’s related to CIFS itself, but I though that using failover groups that move LIF from one node to another the dialog between storage and clients could remain active.

Reading the NDO scenarios TR you’ve linked me it seems that the “nondisruptive” operation related to the LIF migrate (I presume before the takeover on the remaining node) could have issue and clients risk to loose their connection.

I ask this for I’m facing a particular environment where hundreds of VMware View desktop have their folder profile on a CIFS share created on a NetApp FAS (now 7Mode flexvols and in the next weeks on a cDOT SVM).

With customer were discussing some operations to remove or to add some PCI card in the HA first pair of the new cluster and we must schedule this together with a stop of View clients.

This mean that NDO operations, always on and so on is not true if there’s CIFS.

Regards,

Da: Parisi, Justin [mailto:Justin.Parisi@netapp.com]
Inviato: mercoledì 29 luglio 2015 16:57
A: Basil <basilberntsen@gmail.com>; Milazzo Giacomo <G.Milazzo@sinergy.it>
Cc: Toasters <toasters@teaparty.net>
Oggetto: RE: NDO & CIFS

Note that this is an issue with the protocol itself, rather than the storage. This happens across all vendors.

We have a TR that covers CIFS NDO scenarios.

http://www.netapp.com/us/media/tr-4100.pdf

From: toasters-bounces@teaparty.net [mailto:toasters-bounces@teaparty.net] On Behalf Of Basil
Sent: Wednesday, July 29, 2015 7:49 AM
To: NGC-g.milazzo-sinergy.it
Cc: Toasters
Subject: Re: NDO & CIFS

Using anything but the newest version of SMB (which, as far as I know, is windows 2012 only), no. All LIF migrations and node HA failovers entail a reset of the CIFS sessions.

On Wed, Jul 29, 2015 at 6:26 AM, Milazzo Giacomo <G.Milazzo@sinergy.it> wrote:

Hi all,

with cDOT is there a way to avoid that CIFS sessions fall during a takeover?

In 7 Mode when an NDU operation is performed CIFS must is interrupted and open CIFS sessions fall if not closed before.

Is there a way using failover groups of the data LIF to avoid this?

Regards,

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