[CentOS] Re: performance lost in using a software raid array with only 1 disk

Wed Jan 31 16:14:02 UTC 2007
Scott Silva <ssilva at sgvwater.com>

Feizhou spake the following on 1/31/2007 7:09 AM:
> Jerry Geis wrote:
>> Is there any performance lost in using a software raid array
>> with only 1 disk?
>>
>> I was wanting to use the mdadm monitoring tools to monitor the
>> machines single disk drive for failures and such. Is there any
>> performance hit for such a setup?
> 
> I assume you are talking about RAID1 arrays. No, you won't. Rather, you
> will get a performance loss if you carve up your disk into more than one
> partition.
> 
>>
>> Some machines have RAID some machines dont (for me) and
>> I was thinking about a common setup.
>>
>> Also then if I want in the future I can actually just add the second
>> disk and now I have RAID.
> 
> I don't think you can actually build an array with missing disks.
Yes, you can build an array with missing disks, and you shouldn't see much
write difference with a missing drive in raid1, but might see a lower read
performance (lower than having the raid array, but near equal to a single
non-raid drive). With software raid5, you usually see some degradation with
both write and read.

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