Re: Performance Issues
A side-thread on tuning Informix AIO virtual processors. The advice was to set NUMAIOVPS, then watch 'onstat -g iov': if no AIO VP shows an io/wup below 1.0, add more (two at a time); if more than one is below 1.0, you can drop some. Asked why two at a time, Art Kagel explained it confirms you have enough (one spare idle VP), covers peak load, and reduces the number of maintenance windows. Others pointed out no downtime is actually needed — you can add VPs dynamically with onmode and edit $ONCONFIG so the change persists across restarts, which Kagel accepted.
Auto-generated by DrWatson from the posts below — may be imperfect; read the full thread.
[cutting]
>
> NUMAIOVPS 6 # Number of IO vps>
> Then monitor onstat -g iov. If there are more than one AIO VP with an
> io/wup column value less than 1.0 you can drop some. If there are NO
> AIO VPs with io/wup less than 1.0 you need to add more. Add two at a time.
Why 2 at a time ?
--
Paul Watson #
Oninit Ltd # Growing old is mandatory
Tel: +44 1436 672201 # Growing up is optional
Fax: +44 1436 678693 #
Mob: +44 7818 003457 #
www.oninit.com #
Paul Watson wrote:
> [cutting]
>
>>
>> NUMAIOVPS 6 # Number of IO vps>>
>> Then monitor onstat -g iov. If there are more than one AIO VP with an
>> io/wup column value less than 1.0 you can drop some. If there are NO
>> AIO VPs with io/wup less than 1.0 you need to add more. Add two at a
>> time.
>
>
> Why 2 at a time ?
>
I find it comforting when I add that last 2 and one of them is not needed.
Then I know for sure I've got it right should I decide to drop it. Besides,
one extra is insurance against higher peak requirements in case I did not
catch the top peak in my testing. Usually I'll leave on extra online for a
month or so and adding two when I know I need at least one gets me there
faster. Also if I actually need 4 more it only takes two downtime windows
to get me there instead of 4.
Art S. Kagel
"Art S. Kagel" <kagel@bloomberg.net> wrote in message news:41BF06B9.2070105@bloomberg.net... > Also if I actually need 4 more it only takes two downtime windows to get > me there instead of 4. Why do you need a downtime at all to add aio vps?
On Tue, 14 Dec 2004 22:39:57 -0000, "Neil Truby" <neil.truby@ardenta.com> wrote: >"Art S. Kagel" <kagel@bloomberg.net> wrote in message >news:41BF06B9.2070105@bloomberg.net... > >> Also if I actually need 4 more it only takes two downtime windows to get >> me there instead of 4. > >Why do you need a downtime at all to add aio vps? > You could add them dynamically, but then they're lost at the next instance bounce . . . JWC
"John Carlson" <jwcarlson1@yahoo.com.invalid> wrote in message news:rfivr0d9vn92s09ggo11lr4tkdl85jeodk@4ax.com... > On Tue, 14 Dec 2004 22:39:57 -0000, "Neil Truby" > <neil.truby@ardenta.com> wrote: > >>"Art S. Kagel" <kagel@bloomberg.net> wrote in message >>news:41BF06B9.2070105@bloomberg.net... >> >>> Also if I actually need 4 more it only takes two downtime windows to get >>> me there instead of 4. >> >>Why do you need a downtime at all to add aio vps? >> > > You could add them dynamically, but then they're lost at the next > instance bounce . . . Right, but if you change the $ONCONFIG file at the time that you add them dynamically, you won't need a downtime, will you?
Neil Truby wrote:
> "Art S. Kagel" <kagel@bloomberg.net> wrote in message
> news:41BF06B9.2070105@bloomberg.net...
>
>
>>Also if I actually need 4 more it only takes two downtime windows to get
>>me there instead of 4.
>
>
> Why do you need a downtime at all to add aio vps?
>
>
You're right. I always think of that as a permanent fix and rarely onmode
it unless performance is seriously affected. Just stuck in a box is all.
Art S. Kagel
Related threads
- Posting from the Informix-list
- Migrating from IDS 9.40.UC6 to 11.50.UC3
- Ip for a network session
- questions onstat -g