Re: [PATCH] ENBD for 2.5.64

From: Lars Marowsky-Bree (lmb@suse.de)
Date: Wed Mar 26 2003 - 04:59:15 EST


On 2003-03-26T18:31:31,
   Lincoln Dale <ltd@cisco.com> said:

> >Indeed, there are iSCSI implementations that do multipath and
> >failover.
> iSCSI is a transport.
> logically, any "multipathing" and "failover" belongs in a layer above it --

"Multipathing" on iSCSI is actually a layer below - network resiliency is
handled by routing protocols, the switching fabric etc.

> >Both iSCSI and ENBD currently have issues with pending writes during
> >network outages. The current I/O layer fails to report failed writes
> >to fsync and friends.
> these are not "iSCSI" or "ENBD" issues. these are issues with VFS.

Yes, and it is a fairly annoying issue... In particular with ENBD, a partial
write could occur at the block device layer. Now try to report that upwards to
the write() call. Good luck.

Sincerely,
    Lars Marowsky-Brée <lmb@suse.de>

-- 
SuSE Labs - Research & Development, SuSE Linux AG
  
"If anything can go wrong, it will." "Chance favors the prepared (mind)."
  -- Capt. Edward A. Murphy            -- Louis Pasteur
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