[CentOS] md raid1 - no speed improvement

[Steve Thompson]

On Sun, 23 Mar 2008, Ralph Angenendt wrote:

> Kieran Clancy wrote:
>> When I do tests though, I find that the md raid1 read performance is
>> no better than either of the two disks on their own
>
> Why should RAID1 be faster than writing to/reading from a single disc?
> You are *mirroring* each write to another disk, so I'd even expect it to
> be slower.

Read performance would be better if there are multiple accessors, but not 
for just a single stream. The hdparm test is not good in this case; Kieran 
sees exactly what is suspected. Try running it twice (at the same time).

Steve
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