Problem with SATA/SAS 5iR

[Richard Tector]

Kevin Smith wrote:
> Hi,
> 
> I have a problem with a Dell Poweredge SC440 computer.
> It's equipped with a "Dell SATA/SAS 5iR" controller, it's from LSI actually
> (maybe megaraid).
> 
> I'm using FreeBSD 7.1 Release
> 
> I have 2x 500 GB SATA in a synchronised(status optimal) RAID-1 logical
> volume.
> 
> The machine is brand new, first problem arised early after the installer
> started to install the files, the install was very slow, (I know it is
> because write cache is not enabled, that can be done with a management
> program, and I will enable it later) and sysinstall could not install the
> ports collection, the error it gave was
> "write error on transfer to cpio process, try of 1024 bytes"   after OK,
> write error popped up.
> 
> I found this error too, but I found no clue what could have happened.
> 
> Installing the system without the ports collection (installed it later with
> cvsup)in another run gave no error at all, and in dmesg is see the logical
> volume:
> 
> mpt0:vol0(mpt0:0:0): Settings ( Hot-Plug-Spares High-Priority-ReSync )
> mpt0:vol0(mpt0:0:0): Using Spare Pool: 0
> mpt0:vol0(mpt0:0:0): 2 Members:
>       (mpt0:1:32:0): Primary Online
>       (mpt0:1:1:0): Secondary Online
> mpt0:vol0(mpt0:0:0): RAID-1 - Optimal
> mpt0:vol0(mpt0:0:0): Status ( Enabled )
> (mpt0:vol0:1): Physical (mpt0:0:1:0), Pass-thru (mpt0:1:0:0)
> (mpt0:vol0:1): Online
> (mpt0:vol0:0): Physical (mpt0:0:32:0), Pass-thru (mpt0:1:1:0)
> (mpt0:vol0:0): Online
> da0 at mpt0 bus 0 target 0 lun 0
> da0: <Dell VIRTUAL DISK 1028> Fixed Direct Access SCSI-5 device
> da0: 300.000MB/s transfers
> da0: 476837MB (976562176 512 byte sectors: 255H 63S/T 60788C)
> 
> It looks OK, but then I found this after typing "df -h", and it gives me the
> creeps:
> 
> Filesystem     Size    Used   Avail Capacity  Mounted on
> /dev/da0s1a    496M    138M    318M    30%    /
> devfs          1.0K    1.0K      0B   100%    /dev
> /dev/da0s1e    3.9G     14K    3.6G     0%    /tmp
> /dev/da0s1f    440G    537M    404G     0%    /usr
> /dev/da0s1d    2.9G    1.3M    2.7G     0%    /var
> 
> I'm reading the freebsd-current list, and I found another buffer related
> problem there, but they say nothing about these.
> 
> If you have any explanation/solution for these problems pls share them!
> 
> 

What's wrong with the dmesg? The used/available inconsistencies are due 
to space being reserved.

Regarding disk performance, you need to put hw.mpt.enable_sata_wc=1 in 
/boot/loader.conf to reenable the write cache (it's disabled by default 
for consistency reasons when using SATA disks leading to poor write 
performance).

Regards,

Richard