[CentOS] Software Raids Questions (I have only ever used hardware?)

[Christopher Chan]

Ross Walker wrote:
> On Sep 27, 2009, at 8:56 PM, Karanbir Singh <mail-lists at karan.org>  
> wrote:
>
>   
>> On 27/09/09 21:32, aurfalien at gmail.com wrote:
>>     
>>> few things;
>>>
>>> i'm not hip to the latest barney phife shareware utils that may allow
>>> some kind of dynamic raiding bs, but generally, no, you must format
>>> those drive to the desired fs after raiding them so back up all  
>>> data u
>>> want housed (or hozed) on that new raid.
>>>       
>> This is not true. Even with the extremely basic process, you only need
>> to have 1 disk in 'being prepd' state - which means you can, if  
>> there is
>> time and resources, shovel data around on the disks as they get used
>> into the raid setup. Ofcourse, you will need to have 1 disk clear.
>>
>> Eg. to convert this setup into a raid-5 : start with a 1 disk raid-1
>> degraded, move a disks worth of data onto there, bring in the second
>> disk and let them sync into a 'normal' raid1 state, then convert that
>> into a raid-5 with the 3rd disk. then bring in the 4th disk as  
>> hotspare.
>>
>> with TiB's worth of data, its not going to be quick.
>>     
>
> Can you convert a RAID0 to a RAID5?
>
>   
According to Neil Brown, yes.