[Snort-users] Snort and SQL performance

Fraser Hugh hugh_fraser at ...2804...
Wed Sep 5 12:14:04 EDT 2001


Postgres's transaction overhead seems to make a considerable difference to
ACID, which issues a lot of queries building its pages. The DB itself isn't
slow... I've written some perl scripts to generate stats that quickly churn
through endless Code Red alerts, but they're based upon queries written to
use the DB efficiently, something that's more difficult to do from a generic
user query web page. Even with fsync turned off, deleting 40000 Code Red
alerts through ACID is painful, but very quick in Perl. I suspect some
optimization in ACID would bring Postgres and MySQL closer  in performance.

In my environment, I wanted to merge Snort and ACID with DCL (a free trouble
ticket tracking system) to manage the audit trail that we generate when
there's a security alert. A bit of plpgsql to add some triggers to the snort
database , a couple of tables to identify alerts we're interested in
tracking, and I've extended Snort to cut trouble tickets in DCL without
actually changing Snort or any rules. Eventually, I'll get around to a
custom output plugin, but triggers in Postgres seemed much simpler. My
solution for the performance issue has been to use scheduled perl scripts to
do daily pruning of old events to keep the size down.

> -----Original Message-----
> From:	Kevin Brown [SMTP:Kevin.M.Brown at ...1022...]
> Sent:	Wednesday, September 05, 2001 1:01 PM
> To:	'snort-users at lists.sourceforge.net'
> Subject:	[Snort-users] Snort and SQL performance
> 
> Currently running Version 1.8.1-RELEASE (Build 74) on a Netra T1 AC200
> (500MHz Sparc IIe, 1GB RAM, 2x 18GB 10k RPM SCSI drives) and have it
> logging
> to a remote SQL database, MySQL 3.23.40 running on a Quad PII450 Xeon, 2GB
> RAM, 40GB Hard drive space devoted to the database.  I have noticed that
> as
> the database gets larger in size, the performance of snort begins to slip.
> During the summer when few to no students were present, snort was clocking
> along at 70% of the CPU.  The semester has begun and network usage has
> risen, yet snort has slowly gone down from 70% to 45%.  The only thing
> that
> has changed on the network is that the SQL Database has grown from 0
> records
> on 8-13-01 to 2,632,460 records as of an hour and a half ago, listening on
> a
> total of 200Mb of bandwidth to various ISPs that service this campus.  I
> have also tried this with PostgreSQL, but while the insert performance may
> have been better the ACID performance for viewing the data was an order of
> magnitude, or more, worse (e.g. 100s for postgres vs. 10s for mysql).
> 
> To me this suggests that there may still be some tuning options, either in
> mysql or in the spo_database plugin to improve the speed of the inserts to
> see if that keeps snort chugging along happily.
> 
> END OF LINE...
> 
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> 
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