[Xymon] Detecting read-only file system in Linux

[SebA]

Hi,
 
I have been trying to find out if there is a way of Xymon detecting that a
file-system in Linux has gone read-only as a result of a disk error (other
than reporting it just the once via monitoring /var/log/messages).  Nothing
is showing up in my Xymon server, but my xymon-client is a bit old:
xymon-client-4.3.7-26.1.el5.tnt
 
I did a bit of Googling and I came up with these two links that may be
relevant:
http://sisyphus.ru/en/srpm/Sisyphus/xymon/sources/8
https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=764197
 
It seems that a RPM maintainer may have made some modifications to their
version in order to catch disks in a read-only state (in the first link) and
that there is mount-ro plugin that is part of the hobbit-plugins package in
Debian / Ubuntu.  Does anyone have more information on either of these and
whether any patches can be integrated upstream or plug-ins added to
xymonton?  CCing Axel Beckert as he seems to have committed something to the
mount-ro plugin recently: https://www.openhub.net/p/hobbit-plugins/commits
 
Although we have some Debian systems, I was looking for a solution for
another Linux distro.
 
If I was to write something myself to do it, I would check /proc/mounts and
the best command I could find was:
awk '$4~/(^|,)ro($|,)/' /proc/mounts
which outputs:
/dev/root / ext3 ro,data=ordered 0 0
with sample line:
/dev/root / ext3 ro,data=ordered 0 0

This command also produced a nice summary output that might be good to have
on a Xymon status page:
cat /proc/mounts|sort|awk '{print $1 "\011" toupper(substr($4,0,2)

The following was at the bottom of /var/log/messages, but it does not
suggest any very obvious alarm strings to add other than the last line
without the 'dm-0', but it would be nicer to have something more generic
still as textual messages can change between different versions of the O/S.
 
kernel: sd 0:0:0:0: Unhandled sense code
kernel: sd 0:0:0:0: SCSI error: return code = 0x08100002
kernel: Result: hostbyte=invalid driverbyte=DRIVER_SENSE,SUGGEST_OK
kernel: sda: Current: sense key: Hardware Error
kernel:    Add. Sense: Defect list error
kernel:
kernel: Buffer I/O error on device dm-0, logical block 1358756
kernel: lost page write due to I/O error on dm-0


Kind regards,

SebA

 
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