what is the sequence for booting 1

[bhawani123]

Hello Everybody,
I have some ultra 10 and ultra 60 system and external
Hard-Disk and DAT drive are configured in systems.
Someone is telling me After 5 minutes of system booting external devices should be switched on.Is this correct? please tell me appropriate sequence.

Thanks in Advance

Ajay

 

[jhunnu]

Ajay,

It's not like that unless until your Id is clash if your HW ID is not clash you can Switch it on, If you HDD ID is clashing with your Tape you have to Switch off External tape drive otherwise it will not boot.
You can find your HDD+tape Id by;
ok>probe-scsi-all

Thanks

Jhunnu(jhunnu@yahoo.com)

 

[tuka]

You should have all the peripherals powered on prior to boot.
At the ok prompt you can do use these commands to identify
the peripherals

Ultra 10:

ok probe-ide ( will show all IDE devices)
ok probe-scsi-all will show all scsi devices)

Ultra 60:

od probe-scsi-all ( show all scsi devices)

 

[bhawani123]

Hello tuka,

which one have to be power on firstly(system or peripheral devices)?
please explian me why we follow this sequence?

Regd,
Ajay

 

[tuka]

I usually power the drives on first. This is to allow the devices to be up and ready when the the system is powered on and the boot up process started.
This has always been debated in the same manner as which came first the chicken or the egg.

If the system is power first and the EEPROM parameter (auto-boot is set to true then the system will try to boot and the disk will not be ready.

 

[bhawani123]

Hello tuka,

Thanks for your Suggestion.But I heard that firstly system
switch to be ON.
Because firstly system CPU takes times for initialization
and after switch ON the external devices it detect the external devices.

Thanks,
Ajay lohani

 

[marrow]

Hello Ajay,

I think the advice from all the above is spot on especially Tuka - 8 Jan 2002 and should not be ignored.

Power on peripherals first, this is essential, especially on complicated disk systems like Sun Cluster, HA and Veritas, I strongly advise rebooting the system is the last thing you do. By all means allow 5 minutes for disks and hardware to cycle up but boot the system after 5 minutes and not 5 minutes before.

As an example imagine a complete power off situation where all kit is switched off and the first thing you do is kick off with a reboot. The system may not even recognise that some peripherals exist, so up comes an incomplete system, at some stage you'll have to reboot again to reintroduce the missing hardware, this would increase downtime.

As another example when shutting a system down, the reverse would apply, you would "init 0" and once system is back at the boot prompt you'd then power off your peripherals, not before unless you wanted damaged disks.

Basically the answer to your original question "Someone is telling me After 5 minutes of system booting external devices should be switched on. Is this correct?"

The answer is No.

Best of luck

 

[bhawani123]

Thanks to All for Valuable suggestion.

Regd,
Ajay