Some more questions:
1. I couldn't find the config file. Where is it located? Is there any
documentation about it?
2. How can I configure fancy naming for devices (instaed of using
something like /dev/mapper/3600c0ff00000000007c1d121c397f503) in
the config file?
3. How can I config the delay from the time that a device has failed
until the dm moves to the next active device? Again, I understand
that I should use the config file somehow.
I tried to run the following test: I created a multipath device with 2
physical devices (/dev/sda & /dev/sdb). I started running traffic on the
multipath device. All traffic ran through /dev/sda. Then, I disconnected
the iSCSI target that was represented by /dev/sda. After some time, the
traffic was directed to /dev/sdb. I stopped the traffic, disconnected
the iSCSI target that was represented by /dev/sdb and reconnected
/dev/sda. Now, if I run `multipath -l`, I see the following output:
3600c0ff00000000007c1d121c397f503
[size=10 GB][features=0][hwhandler=0]
\_ round-robin 0 [prio=0][enabled]
\_ 0:0:0:0 sda 8:0 [failed][undef]
\_ round-robin 0 [prio=0][enabled]
\_ 1:0:0:0 sdb 8:16 [failed][faulty]
/dev/sdb is dead and I'm ok with it. However, /dev/sda is alive. I was
able to run the following command:
dd if=/dev/sda of=/dev/null count=100000
However, if I run the following command:
dd if=/dev/mapper/3600c0ff00000000007c1d121c397f503 of=/dev/null
count=100000
This is what I get:
dd: reading `/dev/mapper/3600c0ff00000000007c1d121c397f503':
Input/output error
0+0 records in
0+0 records out
0 bytes (0 B) copied, 0.00067 seconds, 0.0 kB/s
Can't it recongnize that a device that has failed (/dev/sda) is back to
life?
Thanks
Erez
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