Random Musings of an Insane Mind

Recently one of our servers had some filesystem corruption – corruption that has occurred more than once over time. As we use hardlinks a lot with link-dest and rsync, I’m reasonably sure the issue occurs due to the massive number of hardlinks and deletions that take place on that system.

I’ve written a small script to repeatedly test things and started it running a few minutes ago. My guess is that the problem should show up in a few days.

#!/bin/bash

RSYNC=/usr/bin/rsync
REVISIONS=10

function rsync_kernel () {
  DATE=`date +%Y%m%d%H%M%S`

  BDATES=""
  loop=0
  for f in `ls -d1 /tmp/2011*`
  do
    BDATES[$loop]=$f
    loop=$(($loop+1))
  done

  CT=${#BDATES[*]}

  if (( $CT > 0 ))
  then
    RECENT=${BDATES[$(($CT-1))]}
    LINKDEST=" --link-dest=$RECENT"
  else
    RECENT="/tmp/linux-3.0.3"
    LINKDEST=" --link-dest=/tmp/linux-3.0.3"
  fi

  $RSYNC -aplxo $LINKDEST $RECENT/ $DATE/

  if (( ${#BDATES[*]} >= $REVISIONS ))
  then
    DELFIRST=$(( ${#BDATES[*]} - $REVISIONS ))
    loop=0
    for d in ${BDATES[*]}
      do
        if (( $loop < = $DELFIRST ))
        then
          `rm -rf $d`
        fi
        loop=$(($loop+1))
      done
  fi
}

while [ 1==1 ]
do
  rsync_kernel
  echo .
  sleep 1
done

After building a system for the new backup servers that utilized an Adaptec 31205 controller, I always prefer to use a kernel that we’ve tuned inhouse.

Upon booting into the kernel I had built, I received:

unable to mount root fs on unknown-block(0,0)

Since the drive size on the array was very large, the Debian Installer automatically created an EFI GUID Partition table, which my kernel was not set up for.

In the kernel makemenu, File Systems, Partition Types, enable Advanced partition selection. Near the bottom is EFI GUID Partition support. Enable that, recompile your kernel and you should be set.

One reboot later and voila:

st1:/colobk1# uname -a
Linux st1 2.6.32.7 #1 SMP Fri Jan 29 21:43:32 EST 2010 x86_64 GNU/Linux
st1:/colobk1# df -h
Filesystem            Size  Used Avail Use% Mounted on
/dev/sda1             462M  232M  207M  53% /
tmpfs                 2.0G     0  2.0G   0% /lib/init/rw
udev                   10M   60K   10M   1% /dev
tmpfs                 2.0G     0  2.0G   0% /dev/shm
/dev/sda8              19T  305G   18T   2% /colobk1
/dev/sda5             1.9G   55M  1.8G   3% /home
/dev/sda4             949M  4.2M  945M   1% /tmp
/dev/sda6             2.4G  204M  2.2G   9% /usr
/dev/sda7             9.4G  237M  9.1G   3% /var