[plug] Good RAID Howto

[Ben Jensz]

With the MegaRAID cards (thats what you've got isn't it?) you can expand 
the RAID5 array whilst it's online.  It will take a while to do 
(especially with the default priority) - meaning it could easily take a 
day or so.  BUT, you have to do it with the Global Array Manager 
software from LSI Logic, you can't do it from the BIOS interface.  So 
you'll have to install the server software for that on Linux, and then 
install the client software on a Windows box to connect to it and manage it.

You will have to reboot the box for the OS to see the increased size of 
the "physical" disk it sees (i.e. the RAID5 array) more than likely.  
Then you can resize the filesystem, but you MUST umount it to do this.  
Depending on how you've got the disk configuration setup, and which 
partition you want to resize... it may not be easily possible to resize 
it though.  You may just have to create new partitions, which you could 
mount under particular large group shares depending on where your disk 
usage is going etc. obviously.

HTH. :)


/ Ben


Kai Jones wrote:

> 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
>