[CentOS] Centos 5 on Large Disks.

Tue Oct 23 09:06:10 UTC 2007
Anup Shukla <anup at iamcool.net>

James A. Peltier wrote:
> James A. Peltier wrote:
>> Anup Shukla wrote:
>>> Hi All,
>>>
>>> Sorry if this has been answered many times.
>>> But i have been going through a lot of pages (via google search).
>>> The more i search, the more its confusing me.
>>>
>>> I have a server with 6 (750G each) SATA disks with H/W Raid 5.
>>>
>>> I plan to allocate the space as follows
>>>
>>> swap 8G
>>> /boot 100M
>>> / 20G
>>> -- and remaining space to /data{1,2,3,N} (equal sizes)
>>>
>>> However after the installation and reboot, i got an error about bad 
>>> partition for /data8
>>>
>>> I had hit the 2T limit.
>>>
>>> Then i found this page at 
>>> http://www.knowplace.org/pages/howtos/linux_large_filesystems_support.php 
>>>
>>>
>>> which speaks of using Parted/LVM2 and XFS.
>>>
>>> If i understand this correctly,
>>> I need to have 1 disk to host the CentOS installation.
>>> And i can use the other 5 disks in a RAID array
>>> (label type gpt...)
>>>
>>> Is it not possible to partition and use the existing RAID 5 volume?
>>>
>>> I really am not sure about how to proceed for this big disk problem.
>>>
>>> Any ideas/links will really help.
>>>
>>> Thank you.
>>>
>>> Regards,
>>> A.S
>>> _______________________________________________
>>> CentOS mailing list
>>> CentOS at centos.org
>>> http://lists.centos.org/mailman/listinfo/centos
>>
>> My understanding is that grub and lilo are not able to boot off of GPT 
>> labeled disks currently.  Given the size of currently available disks, 
>> this will probably change soon, however, for now you need a small 
>> partition to boot a large disk.
>>
> 
> sorry, a bit quick off the trigger, but essentially, if you wanted to 
> use a single RAID-5 volume of this size (even if you configured it as 
> you said) the GPT label for the volume would be what gets you cuz of the 
> boot loader.
> 
> The use of LVM and XFS, just have to do with the way they handle larger 
> disks.  With LVM you can lay out the disks in a bit more fine tuned 
> manner that allows you go get around some limitations in certain file 
> systems.  XFS is just recommended because it is a very good performer 
> and was meant to handle large file systems from its inception.  Feel 
> free to use JFS, ReiserFS or your local don-juan-ho file system you like
> 

I think its finally got into my head now. :)

 From what i understand (after your replies and some more googling)
GRUB cannot boot from gpt labeled drives.
So no matter how i partition them, it just wont boot.

So finally, i am putting a 300G SATA to act as the "system" drive.
Then use the other 750G's to be the big RAID 5 Volume (XFS)

Yes, i lose if the 300G fails, but i think i can do something about that 
later.

Thanks for the replies.

Regards,
A.S