On 26 sep, 20:06, [EMAIL PROTECTED] wrote:

> I do not think this is enough info. Do you just see the above then see
> write errors on the FS? Or do you see a error message about the other
> path failing?

First I get a network disconnection (this is the source of all my
problems I think), then I get the multipath message (it's in round-
robin, so it's switching to use only one NIC) and then the writes
error. Then I stopped the test because the other NIC would go down as
well and, at least with 2.6.18, there were the risk of a kernel panic
if writing on a remote volume without a network connection.

> The above errors are expected and ok because of the nic port going up
> and down, and they only indicate that on one path we got errors and
> that multipath handled it by failing a path.

Exactly :) But the problem is that the network is going up and down..
it isn't supposed to act like this... I'm just testing the remote
storage speed with tiobench, not disconnecting the cable to test how
multipath handles failures. So I was asking for advice because I don't
know if the problem is on the Linux side or on the Infortrend side (as
said, they are directly connected, no switches at all between the two)

> If you run
>
> iscsiadm -m session -P 3

Here it is (sorry for the word wrap)

logs1:~#  iscsiadm -m session -
P
Target: iqn.
2002-10.com.infortrend:raid.sn7612961.012
        Current Portal:
172.16.10.10:3260,1
        Persistent Portal:
172.16.10.10:3260,1
 
**********
 
Interface:
 
**********
                Iface Name:
default
                Iface Transport:
tcp
                Iface Initiatorname: iqn.1993-08.org.debian:
01.5133b441938d
                Iface IPaddress:
172.16.10.1
                Iface HWaddress:
default
                Iface Netdev:
default
                SID:
1
                iSCSI Connection State: LOGGED
IN
                iSCSI Session State:
Unknown
                Internal iscsid Session State: NO
CHANGE
 
************************
                Negotiated iSCSI
params:
 
************************
                HeaderDigest:
None
                DataDigest:
None
                MaxRecvDataSegmentLength:
65536
                MaxXmitDataSegmentLength:
65536
                FirstBurstLength:
65536
                MaxBurstLength:
262144
                ImmediateData:
Yes
                InitialR2T:
No
                MaxOutstandingR2T:
1
 
************************
                Attached SCSI
devices:
 
************************
                Host Number: 1  State:
running
                scsi1 Channel 00 Id 0 Lun:
0
                        Attached scsi disk sdb          State:
running
                scsi1 Channel 00 Id 0 Lun:
1
                        Attached scsi disk sdc          State: running

Target: iqn.
2002-10.com.infortrend:raid.sn7612996.001
        Current Portal:
172.16.0.10:3260,1
        Persistent Portal:
172.16.0.10:3260,1
 
**********
 
Interface:
 
**********
                Iface Name:
default
                Iface Transport:
tcp
                Iface Initiatorname: iqn.1993-08.org.debian:
01.5133b441938d
                Iface IPaddress:
172.16.0.1
                Iface HWaddress:
default
                Iface Netdev:
default
                SID:
2
                iSCSI Connection State: LOGGED
IN
                iSCSI Session State:
Unknown
                Internal iscsid Session State: NO
CHANGE
                ************************
                Negotiated iSCSI params:
                ************************
                HeaderDigest: None
                DataDigest: None
                MaxRecvDataSegmentLength: 65536
                MaxXmitDataSegmentLength: 65536
                FirstBurstLength: 65536
                MaxBurstLength: 262144
                ImmediateData: Yes
                InitialR2T: No
                MaxOutstandingR2T: 1
                ************************
                Attached SCSI devices:
                ************************
                Host Number: 2  State: running
                scsi2 Channel 00 Id 0 Lun: 0
                        Attached scsi disk sdd          State: running
                scsi2 Channel 00 Id 0 Lun: 1
                        Attached scsi disk sde          State: running

> You should see at least two sessions. One session would have sdb and
> the other session should have some other sdX that we did not see
> errors for in the log snippets.

Exactly.. but as I said sdd will fail the same, I just stopped the
test before because I don't have physical access to the machine and a
reboot could be a PITA :)

> If you run
>
> multipath -ll
>

mpath0 (3600d0230ffffffff0413075089029900) dm-0 IFT,S16E-R1130
[size=781G][features=0][hwhandler=0]
\_ round-robin 0 [prio=1][enabled]
 \_ 1:0:0:0 sdb 8:16  [active][ready]
\_ round-robin 0 [prio=1][active]
 \_ 2:0:0:0 sdd 8:48  [active][ready

> Also Konrads suggestion to use 'queue_if_no_path' or no_path_retry
> would fix the problem where if all paths are going offline for a
> legitimate reason then dm-multipath would not fail IO to the FS as
> quickly or at all depending on which setting you use.

I'll try this option to mitigate kernel panics when the problem
happens, thanks.
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