kickstart using raw disks as raid

[Jason Edgecombe]

Tracy R Reed wrote:
> Andre Ruiz wrote:
>> As I understand, linux raid tools operate on partitions only, not on
>> full disks, as hardware based solutions.
>
> That's what I was afraid of. Thanks for the info. I will have to 
> figure out a way to increase the size of the partition in the fly when 
> the time comes that we need to do such a thing.
>
>> In your case, it seems the raid logic would be inside virtual
>> machines, is this correct? You would have double network traffic. You
>> can create one big partition of PV type, and create more small
>> partitions of PV type and make them join the VG each time you grow
>> your disks. The raid would be on each filesystem of LVM. Still a pain
>> in the arse.
>
> Yes, the RAID logic is inside the virtual machines. Double network 
> traffic is no problem as I have two gigabit network interfaces which I 
> can dedicate to the SAN. Yes, creating partitions and adding them to 
> the VG each time is possible but a pain. I'll have to see what else I 
> can work out.
>
>> Hard to switch to raid on the AoE server?
>
> I already have RAID5 on the AoE server. But what if the CPU/RAM/mobo 
> on the AoE server dies? :) This is why one side of the mirror is on 
> one AoE server and the other side of the mirror is on another. If the 
> cpu node dies I can restart the domain on another one very quickly. 
> The only single point of failure in my cluster is the switch and 
> eventually I might even get another one and put half the disk nodes on 
> one and half on the other and cross connect the cpu nodes. :)
>
Hi There,

Even when running a linux box with local drives, you still need /boot as 
a regular or RAID1 partition. This porbably isn't neccessary since 
you're running diskless, though.

I would recommend a solution like I use with VMware.

Pick a convenient size such as 10GB or 20GB, depending on your needs. 
Allocate new hard drives based on need. The first hard drive contains 
partitions  for /boot if necessary and the physical volume for the root 
volume group. When you need more space add a new drive, RAID it if 
neccesary, then add it to the volume group. LVM makes adding and 
removing devices much easier than resizing the devices. If you still 
want to resize devices, add a new device with the desired size, RAID it, 
then remove the old device from the volume group.

Sincerely,
Jason Edgecombe