[Lustre-discuss] Client is not accesible when OSS/OST server is down

[Brian J. Murrell]

On Tue, 2008-04-29 at 14:53 -0500, David_Kewley at Dell.com wrote:
> Perhaps the machine is not hung completely, but is only unable to
> support logins.

I had assumed OP was including "root" logins in their attempts and
already established shell sessions.

> There can be an issue if the login process attempts to access Lustre,
> e.g. because the home directory is on Lustre, or perhaps when a
> directory on Lustre is early in your $PATH.

Indeed, you are right David, for non-root users.

> I'm sure there are details there that a Lustre expert could fill in;
> maybe there are some fail-soft mechanisms that should are designed to
> prevent hangs by returning appropriate error codes.

Well, that is failout vs. failover.  But you have to choose one.  There
is no way Lustre could try to determine which read()/write()s should
"fail soft" vs. block waiting for a recovery.

> So this may be more
> an issue of the login mechanisms being unable to recover when attempts
> to access an expected file or directory give some particular I/O error.

Indeed.  I should not have ruled out that the OP had determined this was
or was not the case.

b.

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