LSI Megaraid 9266-4i Inconsistent write speeds

[Sean Diaz]

I have an LSI Megaraid 9266-4i card with 22 1TB 7200 RPM drives attached as well as two 120GB SSD attached and for the life of me no matter what the configuration is I cannot get the performance to be consistent. When copying a large file it will start out at roughly 500MB/s then proceed to drop down to nothing then stay around 20MB/s for the duration of the transfer. What am I doing wrong? I have configured the two SSD's as a RAID 1 array with cachecade 2.0 enabled on them. Any input or help would be greatly appreciated.

 

[Stereodude]

How long does it stay at 500MB/sec? What kind of array are the 22 1TB drives in? Which way are you copying the data (source, destination, network involvement)? Are you reading or writing data to the large array? Is your large array defragmented?

 

[izx]

To add to that, which expander? What model of SSD and which HDs? How does the array perform if you remove cachecade?

 

[Sean Diaz]

The expander is a SuperMicro that is built into the backplane of my chassis (SuperMicro SC216) and the SSD's are Samsung (MZ-7TE120) which are on the QVL according to Avago. I am still trying to fine tune everything and decide what the best setup is for this in order to get the fastest performance for both read and write. To be honest I am not quite sure what kind of performance I should be expecting out of the unit. Any input would be much appreciated.

 

[Stereodude]

Well, you could answer the questions and provide basic information. For all we know you're copying from the array pushing to a destination over WiFi and your results are normal.