Fix for a filesystem statistic error

[Lutz Mader]

Hello Tildeslash,
customer systems (Linux SLES 11/12 with monit 5.26.0/5.25.2) does not collect the disk statistic well in the past. The disk usage data will collected, but the disk activity data will not.

The "monit.log" file contain sometime some error messages:

[CET Mar 19 15:03:27] error    : filesystem statistic error: cannot read /sys/class/block/as12345avol/stat -- No such file or directory
[CET Mar 19 15:47:33] error    : filesystem statistic error: cannot read /sys/class/block/as12345avol/stat -- No such file or directory
[CET Mar 19 15:53:33] error    : filesystem statistic error: cannot read /sys/class/block/as12345avol/stat -- No such file or directory

"monit -I -vv" give some usefull information also:

Reloading mount information for filesystem '/opt/as12345a'
filesystem statistic error: cannot read /sys/class/block/as12345avol/stat -- No such file or directory

"df -T" give the following information:

Filesystem                        Type  1K-blocks      Used Available Use% Mounted on
/dev/vx/dsk/as12345dg/as12345avol vxfs   52328448   5795415  43628907  12% /usd/as12345a

"ls -la" shows the following:

brw------- 1 root root 199, 20001 Apr 14  2019 /dev/vx/dsk/as12345dg/as12345avol

With "cat /proc/diskstats | grep 20001" I got:

199   20001 VxVM20001 567479 0 6640784 449048 37475 1 169389 1604 0 314528 450084

And (more easy to handle and faster) with “cat /sys/dev/block/199:20001/stat" I got:

567479 0 6640784 449048 37475 1 169389 1604 0 314528 450084

‌

Based on this information I patched the src/device/sysdep_LINUX.c file (I append a unified diff file to patch the sources) and build monit. Monit handle the "vxfs" (Veritas filesystem) correctly, now.

‌

Feel free to use my patch, it is a suggestion only,
with regards,
Lutz

‌

p.s.
The patch reads the activity statistic data from the sysfs and the procfs based on the device major and minor number, but I think reading sysfs works well and is more easy.
Maybe I will remove reading the procfs data in the future, my patch file (vxfs-src-monit-5.26.0.diff) contain the whole patch I used for "src/device/sysdep_LINUX.c".

[Lutz Mader]

Nice to see,
without the fix it looked like this.

Filesystem 'Dienst_Fs'
  status                       OK
  monitoring status            Monitored
  monitoring mode              active
  on reboot                    start
  filesystem type              vxfs
  filesystem flags             rw,delaylog,largefiles,ioerror=mwdisable
  permission                   755
  uid                          0
  gid                          0
  block size                   1 kB
  space total                  400.0 GB (of which 1.9% is reserved for root user)
  space free for non superuser 113.8 GB [28.4%]
  space free total             121.2 GB [30.3%]
  inodes total                 31972776
  inodes free                  31778463 [99.4%]
  data collected               Fri, 31 Jan 2020 09:51:00

And with the fix there is the disk activity data for Veritas Filesystems (vxfs) available, also.

Filesystem 'Dienst_Fs'
  status                       OK
  monitoring status            Monitored
  monitoring mode              active
  on reboot                    start
  filesystem type              vxfs
  filesystem flags             rw,delaylog,largefiles,ioerror=mwdisable
  permission                   755
  uid                          0
  gid                          0
  block size                   1 kB
  space total                  400.0 GB (of which 1.9% is reserved for root user)
  space free for non superuser 113.7 GB [28.4%]
  space free total             121.2 GB [30.3%]
  inodes total                 31955176
  inodes free                  31760862 [99.4%]
  read                         870.8 B/s [16.1 GB total], 0.1 reads/s [268080 reads total]
  write                        2.4 MB/s [6.3 GB total], 35.6 writes/s [105166 writes total]
  service time                 0.021ms/operation (of which read 0.000ms, write 0.021ms)
  data collected               Fri, 31 Jan 2020 09:54:07

Filesystem status details for a "vxfs" filesystem with the read, write and service time activity statistic data.

‌

With regards,
Lutz

[hauk]

Looks good! Please make a pull request instead and to accept we must also have the CLA signed.

[Lutz Mader]

Hello Jan-Henrik,

I try to make a pull request, but it seems to I am not authorized to do this or something is goint wrong. I try to do this via Browser and SourceTree (a tool from Atlassian). I signed the CLA.

Sorry, Lutz

[hauk]

To make a PR, first fork the Monit repo. Use Bitbucket to make a branch of your fork and apply your changes. Then in your branches overview on Bitbucket you can create a PR.

[Lutz Mader]

Hello Jan-Henrik,

I tried to do this, but the pull requests list some more files, I add some changes to src/device/sysdep_LINUX.c only.

See https://bitbucket.org/tildeslash/monit/pull-requests/82

Lutz

[Lutz Mader]

Hello Jan-Henrik,
I got some help, the new request contain the changed source file only, now.

See https://bitbucket.org/tildeslash/monit/pull-requests/83/add-vxfs-statistic-support-for-linux

Sorry, but this is my first experience with a GIT repository,
I used and like SVN in general.

Lutz

[Tildeslash]

Fixed: Issue #877: Add support for VxFS filesystem statistics. Thanks to Lutz Mader for patch. https://bitbucket.org/tildeslash/monit/pull-requests/83/add-vxfs-statistic-support-for-linux/diff

→ <<cset 11fca95d3ece>>

[Lutz Mader]

Hello everybody,
a package with this fix based on 5.26.0 is available now, see https://bitbucket.org/lutzmad/monit/downloads/monit-5.26.0-suse11vxfs-x64.tar.gz

I add the support for the VxFS filesystem statistics and for large PIDs (monit procmatch with PIDs up to 8 digits) also, the sources compiled to support SLES 11 (Linux Kernel 3.0, x86_64 only) systems.

Lutz

[Tildeslash]

Hello,

‌

simplified the implementation with this checkin: https://bitbucket.org/tildeslash/monit/commits/7469b8c86d66 (/sys/dev/block/<major>:<minor>/stat is used now by default as using the device name is unreliable even with non-vxfs filesystem under configuration described in #937 and #725)