[CentOS] preferred software RAID 10?

Sat Jul 26 08:00:04 UTC 2008
Rudi Ahlers <Rudi at SoftDux.com>

Ross S. W. Walker wrote:
> Rudi Ahlers wrote:
>   
>> John R Pierce wrote:
>>     
>>> Rudi Ahlers wrote:
>>>       
>>>> And then, how do I setup the partitioning? Do I setup /boot on a 
>>>> separate RAID "partition"? If so, what happens if I want to replace 
>>>> the 1st 2 HDD's with bigger ones?
>>>>         
>>> each partition is raided seperately with mdadm.... you could make the 
>>> whole thing one LVM partition thats raid10, then use LVM to dice it up 
>>> into file systems.
>>>
>>> if you have 4 drives and are doing software raid10, you won't be 
>>> swapping drives with different sizes without a WHOLE lotta pain.
>>>       
>> Ok, so how do I do this? Let's say I have 4x 160GB HDD's now, and plan 
>> on replacing them with 4x 500GB HDD's in the future?
>>     
>
> Personally I would never put an OS install on a higher RAID then RAID1,
> because it gets too messy to upgrade like you suggested.
>
>   
>> What setup would help with a upgrade in the future?
>>
>>     
>>> /boot shouldn't be mirrored, as the BIOS won't know how to boot it. 
>>> leave /dev/sdb1 the same size as /dev/sda1 and call it /boot2 and try 
>>> to remember to copy /boot to /boot2 each time you update the kernel.
>>>       
>> I understand this, but how do you boot from /boot2 on the 
>> second HDD if the 1st have failed?
>>     
>
> Could you not get a system that had 2 drives for the OS and 4 drives
> for data?
>   
No, unfortunately not :( I have a 2U rackmount case with very limited 
space inside.
> I have setup 4 disk RAID10 systems before, but they were never
> intended to be upgraded (in place at least).
>
> I can forward a couple of recipes, but let me first say that to do
> it from the CentOS install media requires 2 RAID1s and LVM striping
> because the RAID10 option isn't on the media, but it is functionally
> equivalent both in useable space and performance.
>   
Would you mind forwarding me your recipes? I'd love to try it out, and I 
have some time right now to setup the RAID 10 system
> If you want to use the MD RAID10 driver you need to build it from a
> working system then install on it.
>
> -Ross
>
> ______________________________________________________________________
>   

-- 

Kind Regards
Rudi Ahlers

Check out my technical blog, http://blog.softdux.com for Linux or other technical stuff


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