Re: Multiplexed RAID-1 mode

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Hi Neil, 

Are you suggesting I do this?

mdadm --create /dev/md0 --level=10 --raid-devices=2 \
              --parity=f2 /dev/sdc1 /dev/sdd1

I just tried it and it appears dog slow - for example
hdparm -t /dev/md0 claims 18MB/s, and I see a similar 
number in /proc/mdstat for resync speed.

Getting rid of the --parity=f2 parameter, the numbers 
jump up to about 65MB/s which is similar to single drive
transfer rate.

Anyway, I haven't thoroughly benchmarked and I know hdparm
is not to be trusted, but so far it's not obvious to me level=10 
beats level=1 for a two drive array. If you think it is worth 
pursuing I will do so.

Cheers,
Jeff

PS. I care most about small (~5K) file read performance. Think
very busy webserver with hundreds of gigabytes of small files.
And an occasional medium size file of a few megabytes.
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