[Lustre-discuss] upgrade to 1.8.4 and test fallback to 1.6.7.2

[Ms. Megan Larko]

Greetings Johann,

Thank you for your response.

On Mon, Sep 27, 2010 at 1:12 PM, Johann Lombardi
<johann.lombardi at oracle.com> wrote:
> 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.

Yes.  I know that *t.group_upcall=NONE is supported in 1.6.   Our site
at SGI did not have its 1.6.7.2 Lustre configured that way.   The SGI
site was using the default and I wanted to change it after upgrading
to 1.8.4.   I apologize if I was not clear.
>
>> the 1.6.7.2 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 1.6.7.2 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 1.6.7.2 (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 1.6.7.2 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.

Okay....I was getting errors when I attempted to use --erase-params
and --writeconf in 1.8.4 stating that my 1.6.7.2 parameters would have
to be updated (again, my "failover.node" string becomes "failnode"
string).  Just my personal experience so far...

Thank you,
MLarko
>
> Cheers,
> Johann
>