ProGauge SCADA

There's a timeout parameter used by NTP that if things get out of sync by too much, it won't sync them at all.

The default is something low, I think just 128 msec, which is pretty small under some circumstances.

edit the /etc/sysconfig/ntpd on the control VM to sync hardware. Default is no. Once done, please cycle ntpd. You will see an extra line for hardware clock. If possible, all VMs and XenServer should use a local physical time server.

xe host-emergency-ha-disable force=true

sudo mount -o remount,rw /

One table per class Easy to understand because of the one-to-one mapping.  Supports polymorphism very well as you merely have records in the appropriate tables for each type.  Very easy to modify superclasses and add new subclasses as you merely need to modify/add one table. Data size grows in direct proportion to growth in the number of objects.   There are many tables in the database, one for every class (plus tables to maintain relationships).  Potentially takes longer to read and write data using this technique because you need to access multiple tables.  This problem can be alleviated if you organize your database intelligently by putting each table within a class hierarchy on different physical disk-drive platters (this assumes that the disk-drive heads all operate independently).  Ad-hoc reporting on your database is difficult, unless you add views to simulate the desired tables. When there is significant overlap between types or when changing types is common.

-Djava.rmi.server.hostname=xxx

-Djava.net.preferIPv4Stack=true

Add 'noirqbalance' (w/o the quotes) to your kernel cmd-line.

kernel /boot/vmlinuz26 root=/dev/disk/by-uuid/241459a4-d4b5-42cf-a30f-4c6bc0120d1d resume=/dev/sda5 ro vga=792 noirqbalance quiet

/etc/monit/monitrc

check process sshd with pidfile /var/run/sshd.pid start program "/etc/init.d/ssh start" stop program "/etc/init.d/ssh stop" if failed port 22 protocol ssh then restart

Create a VM from the Other install media template

Attach the Ubuntu 10.04 ISO to the DVD drive of the VM

Start the VM