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

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15: Re: Server recommend for dotLRN - with 80.000 users- (response to 1)
Posted by Dario Roig on 01/28/04 10:42 AM
Hi friends!

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?

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16: Re: Server recommend for dotLRN - with 80.000 users- (response to 15)
Posted by Dirk Gomez on 01/28/04 11:10 AM
Install acs-developer-support. Turn it on. Turn on database queries output. Report the output.

What does top on the server say?

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17: Re: Server recommend for dotLRN - with 80.000 users- (response to 16)
Posted by Joel Aufrecht on 01/28/04 11:42 AM
More documentation on how to do developer support and performance debugging:
https://openacs.org/doc/openacs-HEAD/maint-performance.html
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18: Re: Server recommend for dotLRN - with 80.000 users- (response to 15)
Posted by Malte Sussdorff on 01/28/04 11:45 AM
Hi Dario,

do you use multiple harddisks for your 128GB Serial ATA?.

If yes, what is your partitioning and where did you install the system and where the postgres data files (the postgres data file should be on a seperate (set of) harddisk(s)).

Anyhow, this does not explain the performance loss. So doing as Dirk suggests will help us help you.

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19: Re: Server recommend for dotLRN - with 80.000 users- (response to 15)
Posted by Andrew Piskorski on 01/29/04 06:49 AM
Dario, you have some fairly serious server hardware there, but "harddisk of X GB, Serial ATA" doesn't mean much of anything. What type of disks exactly, and most importantly, what RAID controller, and what RAID level (1, 5, 10), and partitioned in what way?

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.