Re: 8 hours tests ends with inconsistent DB.

[Quanah Gibson-Mount <quanah@stanford.edu>]

--On Friday, June 11, 2004 11:56 PM -0700 Trevor Warren 
<trevorwarren@yahoo.com> wrote:


>  Have you bombarded your system with Zero think time
> tests and 200-500+ users. Do you understand the amount
> of stree the system is required to handle when
> 200-500+ users hit a system housing 1million records
> with no think time ????.
>
>  A 15-20 user test i am sure i will get openldap to
> excel at. I want my feedback to help us all scale this
> setup to Enterprise needs.
>
>  BTW: A Zero think time test never can be imitated in
> any real life situation since every user infuses a
> large amount of think time into the action of using an
> application.
>
>  Also...a 200+ user test without Think Time is real
> high load for any system. If it can withstand this
> test as an 8 hour ordeal.....we have a REAL Stable
> System here.

Trevor,

I think one thing to consider here is it is rather a bad design flaw to 
have a single server answering queries.  We have 9 OpenLDAP servers in a 
pool that are all replica's of a 10th server that is the master.  This way 
all incoming writes go to the master, which then spreads them out to the 
slaves via slurpd, and the slaves take the queries.  3 of the slaves are 
dedicated to mail delivery, and they each process around 550k connections a 
day, with about 3 times that many searches.  Also, I find, at least in our 
case, it is generally applications and not users making queries.  If you 
properly set up your environment, your servers are not being bombarded with 
writes and reads.  The load tests I've performed with that type of setup 
still show a single server able to handle 30 hosts constantly pounding 
them, with a query rate of about 177 queries/second when the queries are 
bind+search+unbind.   If the queries are bind+<multiple searches>+never 
unbind, the query rate can jump up to 1k/queries a second.

--Quanah

--
Quanah Gibson-Mount
Principal Software Developer
ITSS/Shared Services
Stanford University
GnuPG Public Key: http://www.stanford.edu/~quanah/pgp.html