Re: Error code 5 when launching EVMS 2.5.5

[email protected] wrote on 05/18/2007 09:16:06 AM:

> Hello folks,
>
> I have a system running Linux 2.6.12.6 with EVMS 2.5.5 with the
> latest patches, and I am getting strange behavior when I launch
> EVMS. It immediately outputs the following:
>
> ------------------------------------------------
> Engine: Error code 5 (Input/output error) when reading the primary copy
of
> feature header on object dm-3.
>
> Engine: Error code 5 (Input/output error) when reading the secondary copy
of
> feature header on object dm-3.
>
> Engine: Error code 5 (Input/output error) when reading the primary copy
of
> feature header on object dm-2.
>
> Engine: Error code 5 (Input/output error) when reading the secondary copy
of
> feature header on object dm-2.
>
> Engine: Error code 5 (Input/output error) when reading the primary copy
of
> feature header on object dm-1.
>
> Engine: Error code 5 (Input/output error) when reading the secondary copy
of
> feature header on object dm-1.
>
> Engine: Error code 5 (Input/output error) when reading the primary copy
of
> feature header on object dm-0.
>
> Engine: Error code 5 (Input/output error) when reading the secondary copy
of
> feature header on object dm-0.
> ------------------------------------------------
>
> I don't quite understand this since there are not regions, volumes,
> or anything defined. Any ideas on what might be causing this?
>
> Thank you!
> -Thomas

Hi, Thomas.

The error can probably be ignored, but it would be good to understand the
cause.  Here is what is happening

As part of discovery the EVMS Engine examines the available objects to see
if they have feature headers on them.  Feature headers are used for
creating EVMS objects (for example, Drive Link objects) and EVMS volumes.
A feature header resides in one 512 byte sector at the end of the object.
EVMS writes two copies of the feature header on an object to provide
redundancy in case one gets trashed.   The primary feature header is in the
last sector on the object.  The secondary feature header is in the second
to last sector on the object.

In your case, the Engine actually got error code 5 (Input/output error)
when it tried to read the feature headers.  Since you say that you have no
EVMS objects or EVMS volumes you can ignore the errors since EVMS would not
find any feature headers even if the read was successful.  However, it is
disturbing that you are getting errors when reading the objects.  Those
errors could be indicative of something going wrong that could cause
problems elsewhere.

You should be able to determine what the dm-? objects are.  Run "dmsetup
ls".  It will list all the device mapper devices giving their name and
(major, minor).  The name of the object in the Engine message is
"dm-<minor>".  You should be able to match up the minor number in the
message with the name of the device in the device mapper list.  Knowing
which devices are getting read errors may give you a clue as to why the
reads are failing.

If you want me to look into it further, please run evms with the debug
level set to "debug", e.g., "evms -d debug", and then gzip and send me the
log file, /var/log/evms-engine.log.  Also send me the output of "dmsetup
ls", and for each device in the output run "dmsetup table <device-name>".

Steve D.

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