Software raid VS hardware raid
Warren Block
wblock at wonkity.com
Wed Jan 30 14:06:46 UTC 2013
On Wed, 30 Jan 2013, Artem Kuchin wrote:
>
> 30.01.2013 1:01, Warren Block:
>> On Tue, 29 Jan 2013, Artem Kuchin wrote:
>>
>>>
>>> 29.01.2013 18:57, Warren Block:
>>>> On Tue, 29 Jan 2013, Artem Kuchin wrote:
>>>>
>>>> The Handbook chapter on gmirror talks about the problems with GPT and
>>>> GEOM metadata. In short: right now, they conflict. It's possible to
>>>> mirror GPT partitions, but be aware that if you mirror more than one
>>>> partition on a drive, a rebuild after replacing a drive could thrash the
>>>> heads as mirrors are rebuilt simultaneously.
>>>>
>>>> http://www.freebsd.org/doc/en_US.ISO8859-1/books/handbook/geom-mirror.html
>>>>
>>>
>>> So,
>>> gmirror+GPT=conflict on last sector
>>> GPT+gmirror = hardrive head kill
>>>
>>> nice...
>>>
>>> So, for no more than 2TB disks the best way to go is GMIRROR of the drive
>>> +PARTITION on top of it?
>>
>> GPT partitions should work, just limit it to one mirrored partition per
>> drive.
>
> Please, clarify what you mean here.
If only one GPT partition on a drive is mirrored with another GPT
partition on another drive, head contention never comes up. There is
only one mirror.
It does nearly eliminate the usefulness of GPT partitioning.
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