Hi
I don't know if I'm misundertanding something. I've got an DS4700 and I'm
switching from RDAC[1] to multipath, since it's natively supported in
the distribution I use
here (SLES 10 SP2).
Since RDAC[1] works perfect, I'm trying to use 'rdac' priority in multipath.
My /etc/multiconf.conf is quite tiny, since I'm building it step-by-step :-) :
blacklist {
devnode "^sda[0-9]*"
}
defaults {
user_friendly_names yes
prio rdac
path_checker tur
}
multipaths {
multipath {
wwid 3600a0b8000327b900000107549f85224
alias mpath0
}
}
I think that using 'prio rdac' makes multipath to use 'mpath_prio_rdac' tool.
# multipath -v2 -ll
mpath0 (3600a0b8000327b900000107549f85224) dm-0 IBM,1814 FAStT
[size=140G][features=1 queue_if_no_path][hwhandler=1 rdac]
\_ round-robin 0 [prio=6][active]
\_ 9:0:0:0 sdb 8:16 [active][ready]
\_ round-robin 0 [prio=1][enabled]
\_ 10:0:0:0 sdc 8:32 [active][ghost]
So the first path has priority 6, as I can confirm:
# mpath_prio_rdac /dev/sdb
6
# mpath_prio_rdac /dev/sdc
1
After the first path (prio=6) failure I get:
# multipath -v2 -ll
sdb: rdac prio: inquiry command indicates error
mpath0 (3600a0b8000327b900000107549f85224) dm-0 IBM,1814 FAStT
[size=140G][features=1 queue_if_no_path][hwhandler=1 rdac]
\_ round-robin 0 [prio=0][enabled]
\_ 9:0:0:0 sdb 8:16 [failed][faulty]
\_ round-robin 0 [prio=1][enabled]
\_ 10:0:0:0 sdc 8:32 [active][ghost]
Ok.. working great, activating the second path. But after the faulty
path is restored:
# multipath -v2 -ll
mpath0 (3600a0b8000327b900000107549f85224) dm-0 IBM,1814 FAStT
[size=140G][features=1 queue_if_no_path][hwhandler=1 rdac]
\_ round-robin 0 [prio=2][enabled]
\_ 9:0:0:0 sdb 8:16 [active][ghost]
\_ round-robin 0 [prio=5][active]
\_ 10:0:0:0 sdc 8:32 [active][ready]
Second path is now priority!!! And of course does not fails back! By
the way, my LUN is configured in
DS4700 in sort a way that the first path *is* the path to preferred controller.
I think path priorities should not change. If so first path goes back
to 'active' status.
Am I misunderstanding something ? Or messing things up?
By the way, here comes the default 'multipath.conf':
#defaults {
# udev_dir /dev
# polling_interval 10
# selector "round-robin 0"
# path_grouping_policy multibus
# getuid_callout "/lib/udev/scsi_id -g -u -s /block/%n"
# prio const
# path_checker directio
# rr_min_io 100
# max_fds 8192
# rr_weight priorities
# failback immediate
# no_path_retry fail
# user_friendly_names no
#}
#blacklist {
# wwid 26353900f02796769
# devnode "^(ram|raw|loop|fd|md|dm-|sr|scd|st)[0-9]*"
# devnode "^hd[a-z][[0-9]*]"
# devnode "^cciss!c[0-9]d[0-9]*[p[0-9]*]"
# device {
# vendor DEC.*
# product MSA[15]00
# }
#}
[...]
#devices {
# device {
# vendor "COMPAQ "
# product "HSV110 (C)COMPAQ"
# path_grouping_policy multibus
# getuid_callout "/lib/udev/scsi_id -g -u -s /block/%n"
# path_checker directio
# path_selector "round-robin 0"
# hardware_handler "0"
# failback 15
# rr_weight priorities
# no_path_retry queue
# rr_min_io 100
# product_blacklist LUN_Z
# }
# device {
# vendor "COMPAQ "
# product "MSA1000 "
# path_grouping_policy multibus
# }
#}
Thanks a lot in advance
Lucas Brasilino
[1] http://www.lsi.com/rdac/ds4000.html
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