Re: RAID 6 mdadm

[Gary Dale <garydale@rogers.com>]

On 10/04/13 10:15 AM, Muhammad Yousuf Khan wrote:
> i was watch a person's video regarding RAID 6 with mdadm
> his configuration was very low, some old system probably
> 2GB RAM, 3x8TB Hard Drives, 4port Ethernet card for channeling.
> and the guy was giving review of his home server. he says he will 
> channel the 4 port Ethernet to achive 4Gbps network throughput. and 2 
> drive redundancy with RAID6.
>
> my question is
> since i can not invest that huge money for testing so just asking from 
> experience users. isn't it going to be a problem because of bottleneck 
> and limited throughput of SATA 7200 rpm 3TB drives?
>
> actually what i need is 4GB LAN throughput with teaming (802.3ad) for 
> data storage to backup VMs and same huge data manipulations will be 
> done. so just confused if it going to work or not.
>
> Thanks,
> MYK

That's an odd setup. Why use RAID6 with only 3 drives? He'd get better 
performance with RAID1 with only 3 drives.

However, your question is about performance. My RAID5 array with SATA 2 
drives gets about 200MBps. SATA 3 performance should be double that.

Caching is critical. Disk access is dramatically slower than memory 
access so that your real throughput will depend on how much disk access 
can be avoided or optimized.