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

Mon Sep 28 04:37:37 UTC 2009
Christopher Chan <christopher.chan at bradbury.edu.hk>

aurfalien at gmail.com wrote:
> yea, it means u never done it yourself.
>   
Yes, I do not do raid5. That does not mean I have not used mdadm. I do 
raid1+0 (not raid10) and I do not see how that disqualifies me from 
pointing out that you have the wrong flags for the intended result.

I also do raidz and will probably grow those arrays when support for 
that is added to OpenSolaris.

Likewise, I have used 3ware and know the difference between using 3ware 
750x/850x for raid5 and using 3ware boards that come with bbu caches.

I have done software raid and hardware raid for clusters of servers for 
a sizable messaging service provider now owned by IBM.

I do not know what makes you think that you can be so full of yourself 
to the point of thinking that you do not ever make mistakes.
>
> On Sep 27, 2009, at 7:02 PM, Christopher Chan wrote:
>
>   
>> aurfalien at gmail.com wrote:
>>     
>>> so you're giving advice based on what you're read?
>>>
>>>
>>>       
>> 1) You do not use --grow to add a device.
>>
>> 2) You do not use --add to grow a device
>>
>> 3) I did not give advice
>>
>>
>>     
>>> know that my advice is stuff i've actually done.
>>>
>>>       
>> Oh no doubt. Does that mean you do not make mistakes?
>>
>> BTW, the question was: Can you convert a RAID0 to a RAID5? and the
>> answer is YES from both Neil Brown and Karanbir's post. The only part
>> where I was wrong was I thought it was already implemented. If you  
>> want
>> to call that 'giving advice' then hey, feel free.
>>     
>>> On Sep 27, 2009, at 6:26 PM, Christopher Chan wrote:
>>>
>>>
>>>       
>>>> Karanbir Singh wrote:
>>>>
>>>>         
>>>>> On 28/09/09 02:12, Christopher Chan wrote:
>>>>>
>>>>>
>>>>>           
>>>>>>> Can you convert a RAID0 to a RAID5?
>>>>>>>
>>>>>>>
>>>>>>>               
>>>>>> According to Neil Brown, yes.
>>>>>>
>>>>>>
>>>>>>             
>>>>> erm, that would be quite interesting, since you cant split the  
>>>>> raid-0
>>>>> without first moving data into some state of sanity first. Can you
>>>>> point
>>>>> out where Neil says its something that mdraid can do at the  
>>>>> moment ?
>>>>>
>>>>>
>>>>>
>>>>>           
>>>> Ah sorry, did not read his blog carefully enough.
>>>>
>>>> http://neil.brown.name/blog/20090817000931
>>>>
>>>> He had a line about RAID0 to RAID5 when I skimmed over it. Looking
>>>> again...it is not implemented yet.
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