Re: [LSF/MM TOPIC] linux servers as a storage server - what'smissing?

[Ric Wheeler <rwheeler@xxxxxxxxxx>]

On 01/24/2012 12:05 PM, Loke, Chetan wrote:
> > > But writes that have to fetch the non-cached data, will
> unnecessarily
> > > issue I/O to the fabric. These orphaned I/O's cause more pain in the
> > > cleanup.
> > > And if caching is enabled on the front-side then it's all the more
> > > painful.
> > >
> > > We can go one extra step and make FS fail read I/O for non-cached
> data
> > > too to avoid more orphan IOs.
> > I don't really see this as a useful state. Read-only without a real
> > backing file
> > system or LUN is hit or miss, that file system should go offline :)
> Last year when I checked, I forget but I think xfs(or ext4) was going
> read-only.
> If this is still the case then you are basically asking FS's to modify
> that behavior.

Not really.

I think that at that state, we need to be able to cleanly umount those file 
systems and clean up the system without requiring a reboot.

Read-only state is not a usable condition for a file system without a backing 
device, just an side effect of our error handling...

ric

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