Hello
We're setting up a redhat 5.1 (x86_64) cluster using a winchester
(infortrend based) storage array (also testing a dothill 2730T with same
results), brocade switch, and lsilogic dual-port fibre cards
device-mapper-multipath-0.4.7-12.el5_1.3
2.6.18-53.1.14.el5xen
This is a fairly new setup for us and I wondered if anyone had any ideas
what might be causing the below problems
1. with readsector0
the path failure (port disabled on switch) is not detected until the
mptfc_dev_loss_tmo value is reached - which by default is 60 seconds
changing the module options (mptfc_dev_loss_tmo=2) makes it work quickly
- but I'm not sure this is the correct thing to do, as it seems
multipath should detect this without requiring the device driver to tell
it about the path loss
in this setup no io occurs until this timeout is reached
2. with directio
the path change appears to be picked up within seconds without requiring
the mptfc_dev_loss_tmo change
no change is required to mptfc_dev_loss_tmo to have the failed path
picked up, but we see this messages constantly in /var/log/messages
until the path is re-instated
Mar 13 10:01:06 offsan2 multipathd: sdf: directio checker reports path
is down
Mar 13 10:01:06 offsan2 kernel: sd 0:0:0:3: SCSI error: return code =
0x00010000
Mar 13 10:01:06 offsan2 kernel: end_request: I/O error, dev sdf, sector 0
# multipath -ll also seems to report the path failure without delay, but
the command itself doesn't terminate until the default 60 second
mptfc_dev_loss_tmo timeout is reached
looking at io transfers , although an rsync is constantly running to the
multipath destination, no data is being transferred, and then we see
copy problems
[root@offsan1 home]# for f in 1 2 3 4 5 6 7 8;do cp test.tar
/virtual0/test${f}.tar;done
cp: writing `/virtual0/test4.tar': Input/output error
cp: cannot create regular file `/virtual0/test5.tar': Read-only file system
cp: cannot create regular file `/virtual0/test6.tar': Read-only file system
cp: cannot create regular file `/virtual0/test7.tar': Read-only file system
cp: cannot create regular file `/virtual0/test8.tar': Read-only file system
running multipath commands
- working
[root@offsan1 ~]# multipath -ll
w_qdisk (3600d023000698afb0949f1324710c500) dm-2 WINSYS,FC3458
[size=100M][features=0][hwhandler=0]
\_ round-robin 0 [prio=2][active]
\_ 1:0:2:0 sdc 8:32 [active][ready]
\_ 0:0:2:0 sdi 8:128 [active][ready]
w_virtual0 (3600d023000698afb0949f117e7c0fc00) dm-4 WINSYS,FC3458
[size=136G][features=0][hwhandler=0]
\_ round-robin 0 [prio=2][active]
\_ 1:0:2:2 sde 8:64 [active][ready]
\_ 0:0:2:2 sdk 8:160 [active][ready]
- failed
[root@offsan1 home]# multipath -ll
sdg: checker msg is "directio checker reports path is down"
sdh: checker msg is "directio checker reports path is down"
sdi: checker msg is "directio checker reports path is down"
sdj: checker msg is "directio checker reports path is down"
sdk: checker msg is "directio checker reports path is down"
sdl: checker msg is "directio checker reports path is down"
w_qdisk (3600d023000698afb0949f1324710c500) dm-2 WINSYS,FC3458
[size=100M][features=0][hwhandler=0]
\_ round-robin 0 [prio=1][active]
\_ 1:0:2:0 sdc 8:32 [active][ready]
\_ 0:0:2:0 sdi 8:128 [failed][faulty]
w_virtual0 (3600d023000698afb0949f117e7c0fc00) dm-4 WINSYS,FC3458
[size=136G][features=0][hwhandler=0]
\_ round-robin 0 [prio=1][active]
\_ 1:0:2:2 sde 8:64 [active][ready]
\_ 0:0:2:2 sdk 8:160 [failed][faulty]
3. multipath.conf
using the defaults of
#defaults {
# udev_dir /dev
# polling_interval 10
# selector "round-robin 0"
# path_grouping_policy multibus
# getuid_callout "/sbin/scsi_id -g -u -s /block/%n"
# prio_callout /bin/true
# path_checker readsector0
# rr_min_io 100
# rr_weight priorities
# failback immediate
# no_path_retry fail
# user_friendly_name yes
#}
then
devices {
#device {
# vendor "DotHill"
# product "R/Evo 2730-2R.*"
#path_grouping_policy failover
# path_grouping_policy multibus
# no_path_retry fail
failback immediate
#}
device {
vendor "WINSYS"
product "FC3458"
#path_grouping_policy failover
path_grouping_policy multibus
#polling_interval 10
no_path_retry fail
#path_checker tur
#path_checker readsector0
path_checker directio
failback immediate
}
}
This is all fairly new to us here, and any assistance is appreciated
Cheers,
Dave
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