Multipath command output - Help with understanding output

[Phil Meyer]

On 10/13/2009 10:17 AM, Dan Track wrote:
> Hi,
>
> I've configured multipath but I'm confused with the following. When I
> run "multipath -v2" I don't get any output, but if I run "multipath
> -v3" I get lot's of output e.g.:
>
> cciss!c0d0: not found in pathvec
> cciss!c0d0: mask = 0x1f
> dm-0: blacklisted
> hda: blacklisted
> loop0: blacklisted
> loop1: blacklisted
> loop2: blacklisted
> loop3: blacklisted
> loop4: blacklisted
> loop5: blacklisted
> loop6: blacklisted
> loop7: blacklisted
> md0: blacklisted
> ram0: blacklisted
> ram10: blacklisted
> ram11: blacklisted
> ram12: blacklisted
> ram13: blacklisted
> ram14: blacklisted
> ram15: blacklisted
> ram1: blacklisted
> ram2: blacklisted
> ram3: blacklisted
> ram4: blacklisted
> ram5: blacklisted
> ram6: blacklisted
> ram7: blacklisted
> ram8: blacklisted
> ram9: blacklisted
> sda: not found in pathvec
> sda: mask = 0x1f
> sda: bus = 1
> sda: dev_t = 8:0
> sda: size = 19534921728
> sda: vendor = HP
> sda: product = MSA2012sa
> sda: rev = J300
> sda: h:b:t:l = 0:0:0:1
> sda: serial = 00c0ffd7ba4f00004575b24a01000000
> sda: path checker = tur (controller setting)
> sda: state = 2
> sda: getprio = /sbin/mpath_prio_alua %d (controller setting)
> sda: prio = 50
> sda: getuid = /sbin/hp_scsi_id -g -u -n -s /block/%n (controller setting)
> sda: uid = 3600c0ff000d7ba4f4575b24a01000000 (callout)
> sdb: not found in pathvec
> sdb: mask = 0x1f
> sdb: bus = 1
> sdb: dev_t = 8:16
> sdb: size = 19534921728
> sdb: vendor = HP
> sdb: product = MSA2012sa
> sdb: rev = J300
> sdb: h:b:t:l = 1:0:0:2
> sdb: serial = 00c0ffd7ba4f00004575b24a01000000
> sdb: path checker = tur (controller setting)
> sdb: state = 2
> sdb: getprio = /sbin/mpath_prio_alua %d (controller setting)
> sdb: prio = 10
> sdb: getuid = /sbin/hp_scsi_id -g -u -n -s /block/%n (controller setting)
> sdb: uid = 3600c0ff000d7ba4f4575b24a01000000 (callout)
> ===== paths list =====
> uuid                              hcil    dev dev_t pri dm_st  chk_st  vend/pr
> 3600c0ff000d7ba4f4575b24a01000000 0:0:0:1 sda 8:0   50  [undef][ready] HP,MSA2
> 3600c0ff000d7ba4f4575b24a01000000 1:0:0:2 sdb 8:16  10  [undef][ready] HP,MSA2
> params = 1 queue_if_no_path 0 2 1 round-robin 0 1 1 8:0 100
> round-robin 0 1 1 8:16 100
> status = 2 0 0 0 2 1 A 0 1 0 8:0 A 0 E 0 1 0 8:16 A 0
> Found matching wwid [3600c0ff000d7ba4f4575b24a01000000] in bindings file.
> Setting alias to mpath0
> sda: ownership set to mpath0
> sda: not found in pathvec
> sda: mask = 0xc
> sda: state = 2
> sda: prio = 50
> sdb: ownership set to mpath0
> sdb: not found in pathvec
> sdb: mask = 0xc
> sdb: state = 2
> sdb: prio = 10
> mpath0: pgfailback = -2 (controller setting)
> mpath0: pgpolicy = group_by_prio (controller setting)
> mpath0: selector = round-robin 0 (controller setting)
> mpath0: features = 0 (internal default)
> mpath0: hwhandler = 0 (controller setting)
> mpath0: rr_weight = 1 (internal default)
> mpath0: minio = 100 (controller setting)
> mpath0: no_path_retry = 18 (controller setting)
> pg_timeout = NONE (internal default)
> mpath0: set ACT_NOTHING (map unchanged)
>
> multipath -ll
> mpath0 (3600c0ff000d7ba4f4575b24a01000000) dm-0 HP,MSA2012sa
> [size=9.1T][features=1 queue_if_no_path][hwhandler=0][rw]
> \_ round-robin 0 [prio=50][active]
>   \_ 0:0:0:1 sda 8:0   [active][ready]
> \_ round-robin 0 [prio=10][enabled]
>   \_ 1:0:0:2 sdb 8:16  [active][ready]
>
> Does that mean multipath is working on /dev/sda and /dev/sdb? Is the
> lack of output for "multipath -v2" a concern?
>
> Thanks
> Dan
>
>    

Yes, multipath -l may not show anything.  multipath -v3 should always 
show similar to the output above, and what you see is that it found two 
paths to the same device, which is good.  It is also going to round 
robin reads and writes, which is also good.

You may want to customize things a bit to make it easier to remember, or 
in case you add another unit or device.

I would suggest adding at least these to /etc/multipath.conf:

multipaths {
     multipath {
         uuid       3600c0ff000d7ba4f4575b24a01000000
        failback        immediate
         rr_min_io        1000
         alias            san1
     }

devices {
     device {
         vendor            "HP"
         product            "MSA2"
         features        "1 queue_if_no_path"
         path_checker        tur
     }
}


This creats the device: /dev/mapper/san1 which can then be partitioned 
and mkfs.

Good Luck!