[dm-devel] udevsettle command takes long time to settle in RHEL 5.9 & 5.10

[Adarsh]

Hi All,

Can you please help me with an issue which I am facing in RHEL 5.9 & 5.10
setups.

udevsettle command takes quite long time (60-150 seconds) to return
sometimes.
This is mostly after creating a LUN & issuing a "rescan-scsi-bus.sh"
Please note that only around 10-20 LUNs are present while this issue is hit.

Looked into the udev logs & looks like the culprit is the following line in
"/etc/udev/rules.d/40-multipath.rules":
     RUN+="/bin/bash -c '/sbin/mpath_wait /dev/mapper/%c; /sbin/kpartx -a
-p p /dev/mapper/%c'"

The rule is getting called multiple times for the same device & hence
udevsettle keeps waiting for all these to finish

Mar 10 13:47:00 x336-207-55 udevd-event[8013]: run_program: '/bin/bash -c
'/sbin/mpath_wait /dev/mapper/360a98000316b61396a2b3946424b6f2d;
/sbin/kpartx -a -p p /dev/mapper/360a98000316b61396a2b3946424b6f2d'

Mar 10 13:47:04 x336-207-55 udevd-event[8033]: run_program: '/bin/bash -c
'/sbin/mpath_wait /dev/mapper/360a98000316b61396a2b3946424b6f2d;
/sbin/kpartx -a -p p /dev/mapper/360a98000316b61396a2b3946424b6f2d'

Mar 10 13:47:04 x336-207-55 udevd-event[8107]: run_program: '/bin/bash -c
'/sbin/mpath_wait /dev/mapper/360a98000316b61396a2b3946424b6f2d;
/sbin/kpartx -a -p p /dev/mapper/360a98000316b61396a2b3946424b6f2d'

Mar 10 13:47:10 x336-207-55 udevd-event[8212]: run_program: '/bin/bash -c
'/sbin/mpath_wait /dev/mapper/360a98000316b61396a2b3946424b6f2d;
/sbin/kpartx -a -p p /dev/mapper/360a98000316b61396a2b3946424b6f2d'


Hence, I commented out the line from "multipath.rules" & it started working
fine:
    RUN+="/bin/bash -c '/sbin/mpath_wait /dev/mapper/%c; /sbin/kpartx -a -p
p /dev/mapper/%c'"

Couple of queries:

1. Please let me know if there are any side effects for commenting out the
above mentioned line.
    Ben mentions that block device addition is now taken care of by NETLINK
events as long as multipath is running & no need for udev to fire off
multipath: https://bugzilla.redhat.com/show_bug.cgi?id=460301

2. Please let me know if this is a known issue. I observe it only in
RHEL 5.9 and 5.10 setups.


Any pointers is highly appreciated.


Setup:
======
Red Hat Enterprise Linux Server release 5.10 (Tikanga)
Kernel \r on an \m

Multipath.conf:
===========
defaults {
        user_friendly_names             no
        queue_without_daemon            no
        flush_on_last_del               yes
        max_fds                         max
        pg_prio_calc                    avg
}
blacklist {
        wwid                            SIBM-ESXSMAW3073NC_FDAR9P6402NE0
        wwid                            SIBM-ESXSMAW3073NC_FDAR9P6402PP2
        devnode                         "^cciss.*"
}
devices {
        device {
                vendor                    "NETAPP"
                product                   "LUN"
                features                  "3 queue_if_no_path
pg_init_retries 50"
                path_grouping_policy    group_by_prio
                prio_callout             "/sbin/mpath_prio_alua /dev/%n"
                path_checker            tur
                failback                      immediate
                hardware_handler     "1 alua"
                rr_weight                    uniform
                rr_min_io                    128
                getuid_callout          "/sbin/scsi_id -g -u -s /block/%n"
       }
}

regards,
Adarsh.
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