[dm-devel] system freeze/console flood when unplugging one path of multipath disk array

[Benjamin Marzinski]

On Tue, Nov 28, 2006 at 12:18:51PM +0100, Rainer Toebbicke wrote:
> Hello,
> 
> I've got a Sun 3510 disk array and a dual-channel Qlogic FC HBA, in a 
> Sun X4100 under RHEL4 U4,  each path connected to the array over a 
> qlogic 5600 switch.
> 
> The devices are seen correctly with multipath -l as far as I can judge.
> 
> 
> When I disable one of the paths during a stress test (in this case, an 
> fsck -y), the system "freezes". Actually, it just sends enough 
> (thousands) error messages of the style
> 
> end_request: I/O error, dev sdb, sector 279446024
> Buffer I/O error on device sdb1, logical block 279445961

You wouldn't happen to be doing IO directly to /dev/sdb1, would you? If
so, you need to be doing IO to a kpartx created device on top of your
multipathed device.

> lost page write due to I/O error on sdb1
> SCSI error : <1 0 0 1> return code = 0x10000
> end_request: I/O error, dev sdb, sector 279446025
> Buffer I/O error on device sdb1, logical block 279445962
> lost page write due to I/O error on sdb1
> SCSI error : <1 0 0 1> return code = 0x10000
> end_request: I/O error, dev sdb, sector 279446026
> Buffer I/O error on device sdb1, logical block 279445963
> lost page write due to I/O error on sdb1
> SCSI error : <1 0 0 1> return code = 0x10000
> end_request: I/O error, dev sdb, sector 279446027
> Buffer I/O error on device sdb1, logical block 279445964
> lost page write due to I/O error on sdb1
> SCSI error : <1 0 0 1> return code = 0x10000
> 
> 
> to the serial console to make it appear completely stuck for hours.
> 
> The fsck does not finish, BTW, it restarts from the beginning as soon 
> as I re-enable the port in the switch.
> 
> root at afs26 ~]# multipath -l
> mpath2 (3600c0ff0000000000a792a1887b34100)
> [size=136 GB][features="1 queue_if_no_path"][hwhandler="0"]
> \_ round-robin 0 [active]
>  \_ 1:0:0:3  sdc 8:32  [active][ready]
>  \_ 2:0:0:3  sdi 8:128 [active][ready]
> 
> mpath1 (3600c0ff0000000000a792a0aac9b4200)
> [size=136 GB][features="1 queue_if_no_path"][hwhandler="0"]
> \_ round-robin 0 [active]
>  \_ 1:0:0:1  sdb 8:16  [active][ready]
>  \_ 2:0:0:1  sdh 8:112 [active][ready]
> ....
> 
> /etc/multipath.conf just contains
> defaults {
>         default_features "1 queue_if_no_path"
>         user_friendly_names yes
> 
> }
> 
> besides the usual blacklist.
> 
> Any ideas?
> 
> -- 
> =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
> Rainer Toebbicke
> European Laboratory for Particle Physics(CERN) - Geneva, Switzerland
> Phone: +41 22 767 8985       Fax: +41 22 767 7155
> 
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