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SubjectRe: 2.4.0-test10 Sluggish After Load
Pardon my speculations (if I am wrong), but isn't this an oracle question?  

Isn't oracle killing the server by trying to clean up 1800 connections all at
once? When they're all connected, most of the work is done by one or two
oracle processes, but when you kill your ddos thing, all of the oracle
listeners (of which there is one per connection), steam in and try to clean up.

I thought oracle had an internal connection limit (on our servers it is set to
440 connections), anyways.

Sean

On Wed, Nov 01, 2000 at 09:00:29AM -0600, matthew wrote:
>
>
> I'm evaluating my company's needs for a new database server which means
> that I get to beat the hell out of the contenders. I'm a long time Linux
> user, and the founder of the Orasoft Project (Oracle Apps for
> Linux). There, I'm no Linux spring chicken. :-)
>
> I wrote stress testing apps that simulates extreme database load. I ran
> it against 2.4.0-test9 and locked it up solid on two occasions. I grabbed
> 2.0.4-test10 and reran.
>
> I was impressed. The distributed stress tester (DDOS) created 1800 Oracle
> connections, and then proceeded to bang on the server by selecting random
> connections and executing SELECT statements.
>
> Load average got to 5.48.
> Memory was depleted, and 200M remained of the 800M swap.
>
> After being pleased by the results, I killed the stress tester. That's
> when things went to hell. After the stresser was dead the server's load
> average spiked to 795! I still had a remote console open so I tried to
> run some things. The pstools would hang for about 20 minutes before
> spitting out data. Just hitting ENTER in my ssh session would take 10
> minutes to register with the server.
>
> The machine shouldn't be under any kind of load right now, yet it's acting
> as though it's getting killed.
>
> I've left it in this condition. It's still accepting SSH connections,
> albeit very slowly. If anyone want to take a look I'll create an account
> and allow SSH. I'd prefer it to be someone that I know, or someone with
> an @redhat||suse||etc e-mail address.
>
> Here's the hardware:
> 2x 500mhz PIII
> 256M RAM
> 100% SCSI
> HP Kayak
> Kernel 2.4.0-test10
>
> Here's some stats just before I killed the stress tester:
>
> [root@oserv02 /root]# pstree
> init-+-atd
> |-crond
> |-gpm
> |-kflushd
> |-klogd
> |-kreclaimd
> |-kswapd
> |-kupdate
> |-6*[mingetty]
> |-1803*[oracle]
> |-portmap
> |-sendmail
> |-sshd---sshd---bash---pstree
> |-syslogd
> |-tnslsnr
> |-wu.ftpd
> `-xfs
>
> [root@oserv02 /root]# w
> 9:40pm up 26 min, 1 user, load average: 4.40, 5.48, 4.10
> USER TTY FROM LOGIN@ IDLE JCPU PCPU WHAT
> root pts/1 matthome.godfrey 9:29pm 1:38 5.94s 4.57s w
>
>
> [root@oserv02 /root]# cat /proc/meminfo
> total: used: free: shared: buffers: cached:
> Mem: 261881856 259772416 2109440 0 212992 24477696
> Swap: 814178304 524578816 289599488
> MemTotal: 255744 kB
> MemFree: 2060 kB
> MemShared: 0 kB
> Buffers: 208 kB
> Cached: 23904 kB
> Active: 15268 kB
> Inact_dirty: 180 kB
> Inact_clean: 8664 kB
> Inact_target: 12036 kB
> HighTotal: 0 kB
> HighFree: 0 kB
> LowTotal: 255744 kB
> LowFree: 2060 kB
> SwapTotal: 795096 kB
> SwapFree: 282812 kB
>
> I'm not on the list, so direct your reply to matthew@mattshouse.com.
>
> Matthew
>
>
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