On Fri, Jun 06, 2014 at 02:46:35PM -0400, Jim wrote:
> On Fri, Jun 06, 2014 at 11:45:49AM +0200, Otto Moerbeek wrote:
> > Hi,
> >
> > I have an PERC 6/i Integrated adapter here:
> >
> > mfi0 at pci2 dev 0 function 0 "Symbios Logic SAS1078" rev 0x04: apic 1 int 0
> > mfi0: "PERC 6/i Integrated", firmware 6.2.0-0013, 256MB cache
> >
> > Which has an OK battery but still reports itself as being in WT mode:
> >
> > # sysctl hw.sensors.mfi0.indicator0
> > hw.sensors.mfi0.indicator0=On (bbu ok), OK
> >
> > # bioctl mfi0 mfi0 | head -2
> > Volume Status Size Device
> > mfi0 0 Online 249376538624 sd0 RAID1 WT
> >
>
> Was this RAID volume previously in WB mode? Is it possible that you've simply
> configured it for WT?
I'm pretty sure I didn't put the volumes in WT mode when I created
them. I recently installed 5.5 on this machine, and noticed the flag.
Before 5.5 the flag was not avaliable.
>
> >
> > Now I cam across this in the relase notes of firmware 6.3.3-0002:
> >
> > 12. All RAID volumes will be presented as write through (WT) to the
> > operating
> > system (Windows and linux) independent of the actual write cache policy
> > of
> > the virtual disk. The controller manages the data in cache
> > independently of
> > the OS and any applications. Please use OpenManage or the BIOS
> > Configuration Utility to view and manage virtual disk cache settings.
> >
>
> I believe this is referring to the caching mode page of the virtual disk as
> seen
> by the SCSI subsystem. Specifically the WCE bit would be set to 0. It doesn't
> sound like a change to the underlying actual write policy.
>
> Are you willing to try the 6.3.3-0002 firmware? This release has some changes
> to address how the remaining capacity of the battery was calculated and
> handled,
> both when determining whether there was sufficient remaining capacity for
> keeping
> the drives in WB and how the controller handles its internal battery learning
> cycle (which, BTW, can trigger a period of time where the drives go WT because
> the process intentionally drains the battern down and recharges).
>
> > So what's the status of this WT/WB flag? Can't it be trusted for PERC
> > 6/i and maybe other adapters? If so, a man page blurp would be needed
> > imo.
This volumes feel pretty fast, so I suspect caching mode is OK. Still
it is confusing to have a flag that doesn't reflect reality.
I'm planning to upgrade the firmware next week. We'll see if that
changes anything. BTW, al battery indicaters are healthy, no learning
cycle going on or something like that.
-Otto
