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80skeys's questions

Martin Hope
80skeys
Asked: 2011-04-21 08:40:18 +0800 CST
  • 1

Running apache2/php/mysql on an Ubuntu instance on slicehost. Monitoring homepage accessibility using offsite monitoring tools which test a TCP connection to port 80. A few times a day the homepage times out (not responsive) or long load time (> 40 seconds.)

I'm monitoring CPU, load average, TCP active opens, network traffic, and memory usage. Not seeing anything that points to a problem. The load average is consistently high on this machine (between 6 and 12) but the timeouts do not occur regularly.

Apache config looks normal with MaxClients 150, StartServers 5, MaxRequestsPerChild 0.

Anyone have any thoughts as to where I should look to fix this and/or what parameters I should be monitoring?

lamp
Martin Hope
80skeys
Asked: 2011-04-05 15:09:46 +0800 CST
  • 0

Anyone have experience using 3ware's SNMP library under SELINUX? I get the following error: 

snmpget -v 2c -c pub hostname TW-RAID-MIB::twRaidUnitStatus.1
Error in packet
Reason: noCreation (That table does not support row creation or that object can not ever be created)
Failed object: TW-RAID-MIB::twRaidUnitStatus.1

If disable selinux and restart snmpd, the snmpget works fine.

I've taken the following steps, none of which fixes the problem:

  • yum update net-snmp
  • yum update selinux-policy
  • /sbin/restorecon -R -v /etc/snmp /var/net-snmp /usr/share/snmp /dev/twa*
selinux
Martin Hope
80skeys
Asked: 2010-12-17 11:11:50 +0800 CST
  • 1

Hardware: Sunfire v20z, dual Opteron 1Ghz, 2GB RAM, 73GB 10k rpm scsi.

Is there a "reasonable" threshold I can use in my monitoring software? It's currently at 500 warning, 1000 critical.

What number of interrupts/sec would be better to use? I know this depends on a lot of things, but hoping there's a ballpark value so I'm not randomly picking numbers from a hat...

linux
Martin Hope
80skeys
Asked: 2010-12-15 10:53:17 +0800 CST
  • 3

OS: CentOS 5.5 64-bit
Software: Postgresql
Hardware: Sun X4200; dual-core AMD Opteron 1Ghz (x4); 8GB RAM; LSILogic raid controller + 2x146GB 10k drives.

Running net-snmp and using Traverse to monitor.

Seeing constant 2,000+ system interrupts per second. Traverse flags this as "critical" (default config) .... Is this number truly something to be concerned about?

looking at high number results for interrupts: 

[~]# cat /proc/interrupts   
           CPU0       CPU1       CPU2       CPU3         
 14:        136   54655160    2332995     722234    IO-APIC-edge  ide0  
 66:        618  329180300   20802132     172490   IO-APIC-level  ohci_hcd:usb2  
 74:       4949   16107320    2295957     846017   IO-APIC-level  ioc0  
 82:         22  662837259        233  129090405   IO-APIC-level  eth0  
 90:        723  505860358          0   18967685   IO-APIC-level  eth2  
NMI:     187529     250006     100435     166795   
LOC: 2140313519 2140313343 2140313287 2140313203   
ERR:          0  
MIS:          0

An additional question about the above output: Why do ide0 and usb2 show constant accrual of interrupts, even though there is no USB device connected, and the IDE device (CDROM) is not in use? This question is for my own curiosity.

linux