[CentOS] Software RAID1 Failure Help

Sat Feb 8 19:27:03 UTC 2014
Ljubomir Ljubojevic <centos at plnet.rs>

On 02/08/2014 07:17 PM, Markus Falb wrote:
>
> On 08.Feb.2014, at 11:25, Mogens Kjaer wrote:
>
>> On 02/07/2014 11:47 PM, Matt wrote:
>>> Having a
>>> single drive is slowing down reads as well, I think.
>>
>> This depends upon how the RAID is set up.
>
> No, mdraid 1 is mdraid 1.
>
>> A standard Linux RAID1 setup does not give better reading
>> performance when reading large files than a single disk.
>>
>> I don't know if the RAID system is cleaver enough to
>> save some seek time.
>
> Process X is utilizing only one single disk, so no performance gain.
> But if you have 2 processes in parallel, then you potentially have a gain, because the process Y can read from another disk.
>
> process X -> disk 0
> process Y -> disk 1
>
>> In order to get better read performance you'll have
>> to set it up as RAID10 with far copies.
>
> Yes, mdraid 10 could be a solution for the "1 process should utilize more than one disk" goal.
> I haven't tried it though, what a shame.
>
> Why is that far copies thing important?
>

Better read from "the horses mouths": 
https://en.wikipedia.org/wiki/Non-standard_RAID_levels#Linux_MD_RAID_10

-- 
Ljubomir Ljubojevic
(Love is in the Air)
PL Computers
Serbia, Europe

StarOS, Mikrotik and CentOS/RHEL/Linux consultant