Re: Raid1 replaced with raid10?

[Bill Davidsen <davidsen@tmr.com>]

Neil Brown wrote:
> On Friday May 4, davidsen@tmr.com wrote:
>   
>> Peter Rabbitson wrote:
>>     
>>> Hi,
>>>
>>> I asked this question back in march but received no answers, so here it
>>> goes again. Is it safe to replace raid1 with raid10 where the amount of
>>> disks is equal to the amount of far/near/offset copies? I understand it
>>> has the downside of not being a bit-by-bit mirror of a plain filesystem.
>>> Are there any other caveats?
>>>   
>>>       
>> Clearly you have reduced capacity, since there's a mirror AND a CRC, 
>> otherwise I don't see any drawbacks. The performance should be much better.
>>     
>
> CRC ??? md/raid10 doesn't have any CRC.
> What CRC are you thinking of?
>   
There is an entire paragraph missing here, no doubt a finger check due 
to trying to post and get out to lunch. I was rambling on about raid6, 
mirroring 1+5, and other things which never made it. The post can be 
scrubbed, I was just rambling on at length about various other solutions 
possible.

Not worth a repost, since I was way over answering his question...
> To answer the original question, I assume you mean "replace" as in
> "backup, create new array, then restore".
> You will get different performance characteristics.  Whether they
> better suit your needs or not will depend largely on your needs.
>
> NeilBrown
>
>   


-- 
bill davidsen <davidsen@tmr.com>
  CTO TMR Associates, Inc
  Doing interesting things with small computers since 1979