# Too low speed with IBM ServeRAID 8k and SAS



## MASTER-UA (Jul 25, 2009)

Hi! Please help me with the problem:
I have installed FreeBSD 7.2 amd64 on IBM server x3650.
There is RAID of SAS HDDs and I have it's speen about 50 mb/s when I copy some file to test it.
It is too low, it has to works with 3,5G bit/s!

I have GENERIC kernel and option ips is on.


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## MASTER-UA (Jul 25, 2009)

Hm... May be it is rather normal speed....


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## User23 (Jul 27, 2009)

SAS works with 3 or 6 GBit/s. But this is only the interface speed. The real transfer rates depending on your harddisk model, raid controller model and the raid type you have choosed.

If you just copied a file from one directory to another on a Raid1 array the speed is ok, because the file have to be read and write at the same time on the same device.


```
systat -vm
```
man systat


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