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Subject: Re: [lustre-devel] [PATCH 41/80] staging: lustre: lmv: separate
 master object with master stripe
From:   Oleg Drokin <oleg.drokin@intel.com>
In-Reply-To: <87eflrrsr7.fsf@notabene.neil.brown.name>
Date:   Sun, 11 Feb 2018 19:06:30 -0500
Cc:     James Simmons <jsimmons@infradead.org>,
        "devel@driverdev.osuosl.org SUBSYSTEM" <devel@driverdev.osuosl.org>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Lustre Development List <lustre-devel@lists.lustre.org>
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To:     NeilBrown <neilb@suse.com>
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> On Feb 11, 2018, at 6:50 PM, NeilBrown <neilb@suse.com> wrote:
> 
> Maybe - as you suggest in another email - it is due to some
> client/server incompatibility.  I guess it is unavoidable with an fs
> like lustre to have incompatible protocol changes.  Is there any
> mechanism for detecting the version of other peers in the cluster and
> refusing to run if versions are incompatible?

Yes, client and server exchange “feature bits” at connect time
and only use the subset of features that both can understand.

Bye,
    Oleg