[Lustre-discuss] upgrade to 1.8.4 and test fallback to

Johann Lombardi johann.lombardi at oracle.com
Mon Sep 27 10:12:23 PDT 2010

On Mon, Sep 27, 2010 at 12:31:53PM -0400, Ms. Megan Larko wrote:
> I attempted to add a new lustre tuning parameter to my system (I
> wanted to add the *t.group_upcall=NONE.)   While the Lustre 1.8.4 read

Please note that *t.group_upcall=NONE is already supported in 1.6.

> the tuning parameters without issue and I could add to the
> parameters under 1.8.4 without issue, if I tried to change a parameter
> requiring that I use the --writeconf option, I learned I had to change
> all the parameters from the syntax to the 1.8.4 syntax.
> (EXAMPLE:   "failover.node" string became "failnode")    Okay.  This I
> can do,   BUT...
> If I have to revert to (due to a security flaw in the linux
> kernel or something...) am I correct in assuming that the lustre 1.8.4
> parameter strings would not be understood by the lustre system
> (can't have s/w reading into the future, right?   Smile)?   If that is

To be clear, lustre 1.8 and 1.6 use the same string format. 1.8 just supports
some additional parameters introduced for to the new features (e.g. OST pools).
Unknown params are supposed to be ignored when downgrading. While it works
fine with most of the new params (like OST pools), there is unfortunately a
bug (i.e. it does not work with at_max), see bug 20449.


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