Hello all,
since md started to support of BadBlockList(Log) I'm trying to find
answer to question:
- is there a possibility to get alarm when md discovers new bad blocks?
Please correct me if I'm wrong but I suspect that answer will be "no".
According to man page possible Events are:
DeviceDisappeared, RebuildStarted, RebuildNN, RebuildFinished, Fail,
FailSpare, SpareActive, NewArray, DegradedArray, MoveSpare,
SparesMissing, TestMessage
There is no special event for new badblocks discover and I've checked
today that bad blocks existence is not the reason to mark device "Fail".
I've made experiments with dmsetup simulating "bad surface": even when
new disk containing 90 percents of unusable sectors is added to array md
makes and finishes recover without kicking disk out. Last event is
SpareActive. Syslog does not contain lines about md found bad blocks on
new disk. Array is clean and active.
I understand that manual command "mdadm --examine-badblocks" reveals
such hidden problem.
But is there a way to make "mdadm --monitor" to warn about bad blocks?
PS. System is Debian Jessie RC1
root@linux-test-vb:~# mdadm --version
mdadm - v3.3.2 - 21st August 2014
root@linux-test-vb:~# uname -a
Linux linux-test-vb 3.16.0-4-amd64 #1 SMP Debian 3.16.7-ckt7-1
(2015-03-01) x86_64 GNU/Linux
root@linux-test-vb:~# cat /etc/debian_version
8.0
PPS. Script used for experiments:
-----8<-----
#!/bin/bash
MDNAME=/dev/md999
DISKSZ=$((64*1024*1024))
#cleanup
echo cleanup
mdadm --stop $MDNAME
dmsetup remove bad_disk4
echo making files and loops
for i in `seq 1 4` ; do
losetup -d /dev/loop$i;
dd if=/dev/zero of=f$i bs=1M count=$((DISKSZ/1024/1024))
losetup /dev/loop$i f$i;
done
echo
echo making faulty disk4 with bb somewhere in the middle...
DEV=/dev/loop4
SECTORS=`blockdev --getsz $DEV` #size in sectors
SECTSZ=`blockdev --getss $DEV` #size of sector
BBPOS=$((SECTORS/2)) #bad block position
BBLEN=$((SECTORS/4)) #bad block region length
echo badblock region from $BBPOS to $((BBPOS+BBLEN)) of $SECTORS
dmsetup create bad_disk4 << EOF
0 $BBPOS linear /dev/loop4 0
$BBPOS $BBLEN error
$((BBPOS+BBLEN)) $((SECTORS-BBLEN-BBPOS)) linear /dev/loop4
$((BBPOS+BBLEN))
EOF
echo
echo making initially degraded raid6
mdadm --create $MDNAME -l 6 -n 4 /dev/loop[123] missing
echo waiting for recover finish...
while [ `cat /sys/block/md999/md/sync_action` != 'idle' ]
do
sleep 1
done
echo adding bb disk
mdadm --add $MDNAME /dev/mapper/bad_disk4
-----8<-----
--
WBR,
Serge Bartosh
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