[ale] Performance issue

[LnxGnome]

Math says you should get your 12Gbps+ out of your 40TB array, and
35Gpbs+ from the 104TB array, assuming 7.2K drives maxing at 170MB/s
internal transfer.

What kind of expanders are you using?
Sector/block alignment?  IRQ conflicts?

What's the single drive performance like?  other RAID configs?

On 8/20/16 5:16 PM, Jim Kinney wrote:
> All,
>
> Getting DISMAL performance from new hardware.
>
> Twin 6-core Xeon E5-2630L v.2 @2.40 GHz
> 128GB DDR4 RAM
> LSI megaraid 2108 in a PCIe v3 slot
> Onboard LSI 3108
> Drives are all 6Gbps SAS2 4TB
> 2 arrays, RAID 6, one is 40Tb, other 104TB
>
> Everything hardware says I should expect a minimum through put of
> 12Gbps on either array.
>
> The max I'm getting from iotop is 784 Mbps.
>
> W. T. F!!!
>
> According to top, the system is basically idle. Ditto from iostat and
> every other tool I check. I'm doing a 'cp -a' from/to same array.
>
> Yes. New location is Luks encrypted. That process is totally asleep
> it's getting so little work. The rng is busy (dev/random is not
> running out (watch -n 1 cat /proc/sys/kernel/random/entropy_avail was
> always above 2048)) but not overloaded or asleep.
>
> Tested going unencrypted to unencrypted with similar performance.
>
> Changed tuned-adm to latency-performance from balanced and the read
> portion of the cp went to 0 bps for 20 seconds until I switched it
> back to balanced mode. So that was a fail. It improved greatly using
> throughout-performance mode (bursts of 250MB/s) but was still showing
> long periods of 0 writes. Load went up from a paltry 8 to 22 so it's
> working more.
>
> But top shows wa values across multiple cores hitting 100 so it's
> hitting a wall somewhere.
>
> Any ideas of more places to look?
>
>
>
>
> -- 
> Sent from my Android device with K-9 Mail. Please excuse my brevity.
>
>
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