Re: prestoserve corrupts advfs on raid set

From: Aidan Williams <aidan_at_huon.cse.unsw.EDU.AU>
Date: Mon, 20 Mar 1995 15:32:08 +1000 (EST)

Excerpts from mail: 19-Mar-95 prestoserve corrupts advfs .. Steve
Palmer_at_mdsol1.mdc. (782*)

> We have experienced a major problem with Prestoserve under OSF/1 V 3.2.
> With Prestoserve enabled, our ADVFS on top of a SWXCR RAID set gets
> corrupted. It is very devastating and very reproducible.
> Environment:
> Alpha 2100 model 4/200
> EISA based SWXCR
> EISA based Prestoserve
> OSF/1 3.2 Rev 214
> Firmware 3.9
> PAL code 1.35
> ECU version 1.7
> Scenario:
> Prestoserve active against RAID ADVFS file system mount point
> Build file domain
> Make file set
> mount ADVFS
> reboot twice
> It's gone
> or:
> Mount ADVFS
> Enable Prestoserve
> Dismount ADVFS
> Disable Prestoserve
> It's gone

> We can run Prestoserve on a non-RAID ADVFS with no problems. I have
> called DEC support; they have forwarded problem to engineering. Anybody
> got any ideas. I'm running just find with Prestoserve disabled.

This is not related to AdvFS .... Happens with UFS too, and OSF 3.0b.
It appeared to be related to flushing of cache data to disk from the
EISA NVRAM.

A workaround (from DEC Australia):

        # dbx -k /vmunix
        dbx> patch prflags=1
        dbx> assign prflags=1
        dbx> quit

You'll need to do this every time you rebuild your kernel. This hack
makes prestoserve work in `bounceio'. Any data written to the
prestoserve cache is also copied to main memory -- from where it can
successfully be written back to disk. DEC assure me that a patch will
be available soon.

Sounds like quality control didn't catch this one..
Hey, did they even switch the computer on before shipping?

regards
        aidan
____
:wq! aidan_at_cse.unsw.EDU.AU
Received on Mon Mar 20 1995 - 00:39:57 NZST

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