I need help with 2600 PERC 4 Di

[ChasMartel]

OK bear with me. I've never worked on a Dell server before.

I just inherited two Dell PowerEdge
2600's with 4 36GB disks using PERC 4 Di RAID. At least that is what I thought by looking at DMESG
and the BIOS on a reboot.


So, I opened one up -- after reading the manual -- and was suprised to find no PCI board. I thought I would after
having read the docs. I did find the RAID "key" and the
single stick of mem. I'm missing something here. Why do
I not see a RAID board plugged into a PCI slot?

Is it all on the MB and just activated by the RAID "key"?

Note: They are just humming along and have been for about
a year and a half. I am just investigating their status
in anticipation of replacement or redeployment activity.

I hope RH or Fedora fix the megaraid driver problem so I can
update to a 2.6 kernel. Any comments?

Any helps, tips and/or links will be very much appreciated.

Thanks!

 

[technome]

The Perc4 DI and DC are basically the same, the DC being a addin board with SCSI interfaces on the board. The DI is an embedded controller, which uses the motherboards onboard scsi interfaces, all chips involved in raid are on the motherboard. They use the same Windows drivers. In the event of a fried mobo, you either get a mobo with an embedded raid, either a Dell mobo or a motherboard with an embedded LSIlogic raid interface matching the raid series. Perc raids are Lsilogic OEM, at least the raid interfaces involved here.
Arrays setup on the embedded raid, will work on the Perc4 DC or Lsilogic matching models. The lsi model would most likely be the u320-2x or u320-2 (Dell's Perc 4,has been used for a couple different raid series). The Perc4 array sets should work on the Perc4E or the lsilogic u320-2E,PCI Express models, but you would need to verify this.

The embedded models are a cheap option, but as you can see there is a price to pay, Dell wants you to buy another motherboard from them if something goes wrong.

........................................
Chernobyl disaster..a must see pictorial

http://www.kiddofspeed.com/default.htm

 

[ChasMartel]

So can I remove the RAID "key" and memory stick
and the thing will revert back to nonRAID
operation?

The reason I ask is because there seem to be many problems
with hardware RAID support in most newer linux's. At least of
LSI and Dell boxes.

I also think I will get better support for management of the
RAIDs by using sotware raid instead of hardware raid. Seems
like there is much work and use of mdadm going on right
now. Comments?

 

[technome]

Yes you could disable the raid function but you would need to rebuild the array completely.

If you can not get Linux to run a raid controller, the following is mute...

hardware raids have the coprocessor onboard for a reason, the embedded Perc4e also has one. It takes care of the parity creation. If you use OS involved raid 5, the motherboard CPU will be used for this purpose, >25% of you CPU cycles are used to run OS raid. Other motherboard resources are also taxed by software raid such as memory use, system bus traffic. OS based raid uses more IRQ interrupts then hardware raid.
Another factor is the OS involment..hardware raids are fairly independent of the OS, if the OS corrupts, the raid array does not. With OS involvement, corruption can take out an array set.



........................................
Chernobyl disaster..a must see pictorial

http://www.kiddofspeed.com/default.htm