[plug] Good RAID Howto

[Kai Jones]

OK, forgot all that...yesterday arvo I told everyone to go home a bit 
early, rebooted the file server and had a look. We're running RAID5 
across three disks and the hardware RAID config only allows two options, 
RAID5 or RAID0. So much for having ideas about using RAID 1 on the new 
disks.

As mentioned before, although I understand the principle of RAID I've 
never configured it before, last night's look at the hardware RAID 
config menu's didn't look all that friendly.

The RAID config see's the new disks as being in the READY state but I'd 
have to initialise them, format them (?) and allocate them as RAID5 from 
RAID BIOS to have them available to play with using mdadm once in CLI ?

Any feedback is appreciated !

Thanks
Kai

Kai Jones wrote:
> Running RAID1 as far as I can tell, but are there any commands I can use 
> or any way to actually check that other than knowing we've got 3 x 36 
> gig SCSI disks which are synced and all showing as being one disk with 
> three logical mount points ?
> 
> Thanks for the info on GAM, I'll check it out.
> Cheers
> 
> Kai
> 
> Ben Jensz wrote:
>> So are you running RAID5 or RAID1 with a hot spare?  If you're running 
>> RAID5 you should have approximately 73Gb of space with 3x 36Gb drives in 
>> RAID5, or if you're running RAID1 with a hot spare then you'd only have 
>> 36Gb.
>>
>> Look up the Global Array Manager (GAM) software on LSI Logic's web site 
>> for the MegaRAID card you've got and install that.  You'll have to 
>> install the server software for Linux on the box and run the client 
>> software to connect to the server on a Windows machine as there isn't a 
>> client for Linux.
>>
>> But from there you can check out the current status and setup of 
>> physical drives on the RAID controller without having to reboot the 
>> box.  You should be able to see the additional drives attached to the 
>> controller that you've added as well.
>>
>>
>> / Ben
>>
>>
>> Kai Jones wrote:
>>
>>> Ummm, lemme see if I can clear something up.
>>>
>>> The current file system is not using three logical drives, on one 
>>> physical disk.. It's using three physical drives, each drive mirrored 
>>> to reflect the first drive which has three logical drives. So if one 
>>> drive dies for whatever reason we still have two other, seperate, 
>>> physical drives, that are identical and can keep working.
>