performance with LSI SAS 1064

[Eric Anderson]

Lutieri G. wrote:
> I've make a test with dd command:
> 
> # time dd if=/dev/zero of=./8gbfile bs=1024k count=8192
> 8192+0 records in
> 8192+0 records out
> 8589934592 bytes transferred in 155.653213 secs (55186362 bytes/sec)
> 0.007u 25.129s 2:35.69 16.1%    55+6039k 117+68628io 0pf+0w
> 
> in other terminal i ran iostat while dd were running and I get this:
> 
> # iostat -I 1
>       tty             da0            pass0             cpu
>  tin tout  KB/t xfrs   MB   KB/t xfrs   MB  us ni sy in id
>    1   61 25.23 52958 1305.07   0.00   0  0.00   0  0  8  0 91
>    0  184 127.48 434 54.03   0.00   0  0.00   0  0  5  0 95
>    0   61 127.49 440 54.78   0.00   0  0.00   0  0  5  0 95
>    0   61 127.75 445 55.52   0.00   0  0.00   0  0  5  0 95
>    0   61 127.49 442 55.03   0.00   0  0.00   0  0  4  0 96
>    0   61 127.49 436 54.28   0.00   0  0.00   0  0  5  0 95
>    0   61 125.27 425 51.99   0.00   0  0.00   0  0  5  1 94
>    0   61 118.14 393 45.34   0.00   0  0.00   0  0  3  0 97
> 
> average  54MB/s with or without hw.mpt.enable_sata_wc seted in loader.conf file.
> 
> is it a normal speed for this adapter?!
> 
> 


I'm confused - you said in your first post you were getting 3MB/s, where 
  above you show something like 55MB/s.

You didn't say what kind of disks, or how many, the configuration, etc - 
so it's hard to answer much.  The 55MB/s seems pretty decent for many 
hard drives in a sequential use state (which is what dd tests really).

Your errors before were probably caused because your queue depth is set 
to 255 (or 256?) and the adapter can't do that many.  You should use 
camcontrol to reduce it, to maybe 32.  See the camcontrol man page for 
the right usage.  It's something that needs setting on every boot, so a 
startup file is a good place for it maybe.

Eric