Forum .LRN Q&A: Server recommend for dotLRN - with 80.000 users-

I would like some help in choosing a server for a dotLRN site that would have around 80,000 registered users. Postgres is the preferred database. What would be a good server to recommend for use with Debian Linux?

Thanks

/Dario

Thank you to help me, but I have more questions, please.

-That linux version has for 64 bits (Dual Processor Opterons)?
-Suse 64 bits, maybe?

-In your institution how many users you have?

-Where I can find instructions for change a 'The filesystem based version'?

Thanks.

Since Malte is referring to AIESEC, let me give you some more concrete info:

We have 120K registered users. Only about 20K are active since it is also an alumni database. Our webserver is a Dual-P3 with around 933 Mhz each and 2 GB RAM. Our database server is a Dual-Opteron system as Malte already mentioned.

With this setup we support about 70 concurrent users on OACS 4.6.3 and .LRN 1.0 without any noticable negative impact on performance. When more users try to access the website, performance will decrease considerably. I found out that the webserver is the bottleneck because even when the website is almost not responding anymore at all (around 90 concurrent users) the database is still doing fine. Testing a second webserver at the same time was showing great performance on the second webserver.

We are currently installing a load-balanced solution which will make us very flexible on the frontend (webserver) side. It's just a matter of time until the database will become the bottleneck.

If anyone is interested, I will let you know about the results of our load-balancing and how many users we can handle with it.

Specs:
webserver (~.LRN 1.0/OACS 4.6.3):
dual Xeon CPU 2.8 GHz, 3 GB RAM (dell 2650)

oracleserver (8.1.7.3):
dual Xeon CPU 2.8 GHz, 4 GB RAM (dell 2650)

(Both also has hyperthreading turned on and a dedicated 1 Gbit network between the two)

On heavy loads we find that it's the oracleserver that has the highest load. I'm wondering if the is anything more to gain by tweaking the aolserver-config:

ns_param  maxconnections    50
ns_param  maxdropped        0
ns_param  maxthreads        50
ns_param  minthreads        10
ns_param  threadtimeout      120
...
ns_section ns/db/pool/pool1
ns_param  connections        6
...
ns_section ns/db/pool/pool2
ns_param  connections        16
...
ns_section ns/db/pool/pool3
ns_param  connections        5

Some pics:
http://elg.uib.no/~edpck/logins-week.gif
http://elg.uib.no/~edpck/load-week.gif (green: webserver, blue: oracleserver)

All feedback appreciated

Cheers

ok, will do. thx.

<blockquote> Why do you have so many more connections in your 2nd
database pool than in your first? That seems weird.
</blockquote>

have turned on logging when pools are empty:
ns_param  WarnEmpty          true
- and based on the numbers of warnings tried to adjust the settings.

It's mrtg with a custom script to gather information about the load from the two machines (runs uptime via ssh connections and greps for the load).

Thanks to all for your recommendations.

we already have our system in:

The Database (Postgres 7.4.1):
  -Dual Opterons
  -4 GB RAM
  -Harddisk of 128 GB SerialATA
  -S.O. Mandrake 64 bits

The AOLserver 3.3 y dotLRN 2.0 Beta4:
  - Pentium IV
  - 1GB RAM
  - Harddisk 120GB
  - S.O. Debian

We with 80.000 users and 10.000 groups have perfomance problems with alone a concurrent user. When the user carries out the petition of it paginates web inside a dotlrn course, the slow answer but of 10 seconds.

some suggestion, please?

More importantly, such a horribly awful slowdown (10 s page serve time) with just two concurrent users is pretty strange. That's not some disk IO limit due to e.g. RAID 5 vs. RAID 10 either (not with only 2 concurrent users!), it's got to be something that effects low-end performance too, aka, a mis-configuration problem.

I bet your AOLserver thread settings are wrong, that's probably the easiest single way to make your performance really suck. See my previous post and link above about that.

I have tried your code but dont works:

(I have replaced $subsite_node_id by community_id)

wrong # args: should be "llength list"
    while executing
"llength "
    ("eval" body line 1)
    invoked from within
"eval $script"
    invoked from within
"ns_cache eval util_memoize $script {
        list $current_time [eval $script]
    }"
    (procedure "util_memoize" line 20)
    invoked from within
"util_memoize "llength [site_node::get_children -all -filters { package_key "curriculum" } -node_id $community_id]""

???????????
Best regards,
Agustin

(What is the statement of the curriculum-portlet/module anyway?)

Try putting it in a single line. I get the same error as you do when I use line breaks.

Dirk: I would like to label the package as having a couple of known flaws (and as of today i count the issue at hand as one such flaw) but being basically fit for fight, although I'm not aware of anyone who's banged on it heavily under real-life circumstances yet.

The curriculum-portlet should work but has probably undergone even less testing.

I think one may say the pair's slowly approaching 1.0 status ...

Sorry but I wrote the command in the code in one single line.
But I cut it to send the message to the forum.

set curriculum_bar_p [util_memoize "llength
    [site_node::get_children -all -filters { package_key
    "curriculum" } -node_id $community_id]"]

The problem go on.
Any help?

Agustin