mfi timeouts

[rihad]

On 02/27/2013 12:48 AM, John Baldwin wrote:
> On Tuesday, February 26, 2013 1:31:44 pm rihad wrote:
>>> On 28/10/2011 04:14, Jan Mikkelsen wrote:
>>>> /  Hi,
>>> />/
>>> />/  There is a patch linked to from this PR, which seems very similar:
>>> />/
>>> />/  http://www.freebsd.org/cgi/query-pr.cgi?pr=kern/140416
>>> />/
>>> />/  http://lists.freebsd.org/pipermail/freebsd-scsi/2011-
> March/004839.html
>>> />/
>>> />/  The problem is also consistent with running mfiutil clearing the
> problem.
>>> />/
>>> />/  I'm about to deploy mfi controllers in a similar configuration, so
> I'd be very curious about whether the patch fixes the problem for you.
>>> />/
>>> /This looks promising, I'll give a try when I get a moment.
>> Hi,
>>
>> Did the patch help? We're having the same issues & running "mfiutil show
>> volumes" every minute doesn't make the freezes go away.
>> Will this small patch be ok on 8.2-RELEASE-p4? Thanks.
> You can use the patch on 8.2.
>

Thanks, I was forced to apply the patch to 8.2-p4 and rebuild the kernel 
yesterday in the night, as it sometimes locks up both interfaces in 
periods of high disk/net activity (around 4-5 gbit/s passing through). 
Has anyone had full system lock-ups besides the i/o stall & mfi timeout 
errors? I hope those issues are related. In such cases sometimes one of 
the interfaces lives, sometimes both are down. Happened 2-3 times during 
a little over a month.


Now about this part taken from here 
http://lists.freebsd.org/pipermail/freebsd-scsi/2011-March/004839.html
 > By issuing a dummy read operation (thus forcing a flush of data 
buffers), this issue is largely averted.

Does this mean that battery-backed cache (BBU) is effectively rendered 
useless, as all write operations are forced on to the disk platters on 
every interrupt?

# mfiutil show adapter
mfi0 Adapter:
     Product Name: Integrated Intel(R) RAID Controller SROMBSASMP2
    Serial Number:
         Firmware: 8.0.1-0033
      RAID Levels: JBOD, RAID0, RAID1, RAID5, RAID6, RAID10, RAID50
   Battery Backup: present
            NVRAM: 32K
   Onboard Memory: 512M
   Minimum Stripe: 8K
   Maximum Stripe: 1M