[CentOS] Multipathing with Sun 7310

Thu May 27 14:12:19 UTC 2010
Jens Neu <jens.neu at biotronik.com>

Dear list,

we have a relatively new Sun Storage 7310, where we connect CentOS 5.5 
Servers (IBM LS21/LS41 Blades) via Brocade Switches, 4GBit FC. The Blades 
boot from SAN via qla2xxx, and have no harddisks at all. We want them to 
use multipathing from the very beginning, so /boot and / are already seen 
by multipathd. Problem is, that the Sun 7310 has two storage heads which 
run in active/passive mode. BUT the multipathd thinks, they are 
active/active and therefor shows half the available paths as faulty 
(multipath -ll below)
While this probably gives me the redundancy that is desired, it is a 
relatively messy situation, since it will be unnecessary hard to detect 
real path failures and the OS is complaining about "readsector0 checker 
reports path is down" which gives me >40M/24h /var/log/messages garbage.
Any hints for a reasonable configuration? Unfortunately the Sun 7310 is 
rather new, so almost nothing shows up on google... even less for 
RHEL/CentOS :-(

regards from Berlin
Jens

[root at dev-db1 tmp]# multipath -ll
sdaa: checker msg is "readsector0 checker reports path is down"
sdab: checker msg is "readsector0 checker reports path is down"
sdac: checker msg is "readsector0 checker reports path is down"
sdad: checker msg is "readsector0 checker reports path is down"
sdd: checker msg is "readsector0 checker reports path is down"
sdh: checker msg is "readsector0 checker reports path is down"
sdl: checker msg is "readsector0 checker reports path is down"
sdp: checker msg is "readsector0 checker reports path is down"
sdq: checker msg is "readsector0 checker reports path is down"
sdr: checker msg is "readsector0 checker reports path is down"
sds: checker msg is "readsector0 checker reports path is down"
sdt: checker msg is "readsector0 checker reports path is down"
sdu: checker msg is "readsector0 checker reports path is down"
sdv: checker msg is "readsector0 checker reports path is down"
sdx: checker msg is "readsector0 checker reports path is down"
sdz: checker msg is "readsector0 checker reports path is down"
mpath0 (3600144f0fdf58b5c00004bc738070001) dm-0 SUN,Sun Storage 7310
[size=50G][features=0][hwhandler=0][rw]
\_ round-robin 0 [prio=1][active]
 \_ 0:0:1:0 sda  8:0    [active][ready] 
\_ round-robin 0 [prio=1][enabled]
 \_ 1:0:0:0 sde  8:64   [active][ready] 
\_ round-robin 0 [prio=1][enabled]
 \_ 0:0:2:0 sdi  8:128  [active][ready] 
\_ round-robin 0 [prio=1][enabled]
 \_ 1:0:1:0 sdm  8:192  [active][ready] 
\_ round-robin 0 [prio=0][enabled]
 \_ 0:0:3:0 sdq  65:0   [failed][faulty]
\_ round-robin 0 [prio=0][enabled]
 \_ 1:0:2:0 sdr  65:16  [failed][faulty]
\_ round-robin 0 [prio=0][enabled]
 \_ 0:0:4:0 sdx  65:112 [failed][faulty]
\_ round-robin 0 [prio=0][enabled]
 \_ 1:0:3:0 sdz  65:144 [failed][faulty]
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