How do I configure multipath in testing VM (purpose is purely academical)?I made new logical volume, modified multipath.conf to be as follows:defaults {    udev_dir         /dev    user_friendly_names  yes}blacklist {}blacklist_exceptions {    device {        vendor VMware,        product VMware Virtual S    }}and multipath -v3 says:Apr 22 03:22:24 | sdb: rev = 1.0Apr 22 03:22:24 | sdb: h:b:t:l = 2:0:1:0Apr 22 03:22:24 | (null): (VMware,:VMware Virtual S) vendor/product whitelistedApr 22 03:22:24 | sdb: serial = Apr 22 03:22:24 | sdb: get_stateApr 22 03:22:24 | sdb: path checker = directio (config file default)Apr 22 03:22:24 | sdb: checker timeout = 180000 ms (sysfs setting)Apr 22 03:22:24 | sdb: state = runningApr 22 03:22:24 | directio: starting new requestApr 22 03:22:24 | directio: io finished 4096/0Apr 22 03:22:24 | sdb: state = 3Apr 22 03:22:24 | sdb: getuid = /lib/udev/scsi_id --whitelisted --device=/dev/%n (config file default)Apr 22 03:22:24 | /lib/udev/scsi_id exitted with 1Apr 22 03:22:24 | error calling out /lib/udev/scsi_id --whitelisted --device=/dev/sdbApr 22 03:22:24 | sdb: state = runningApr 22 03:22:24 | /lib/udev/scsi_id exitted with 1Apr 22 03:22:24 | error calling out /lib/udev/scsi_id --whitelisted --device=/dev/sdbApr 22 03:22:24 | sdb: detect_prio = 1 (config file default)Apr 22 03:22:24 | sdb: prio = const (config file default)Apr 22 03:22:24 | sdb: const prio = 1Apr 22 03:22:24 | dm-0: device node name blacklistedApr 22 03:22:24 | dm-1: device node name blacklistedApr 22 03:22:24 | dm-2: device node name blacklisted===== paths list =====uuid hcil    dev dev_t pri dm_st chk_st vend/prod/rev            dev_st      2:0:0:0 sda 8:0   1   undef ready  VMware,,VMware Virtual S running     2:0:1:0 sdb 8:16  1   undef ready  VMware,,VMware Virtual S running[root@localhost ~]# I want to configure multipath for logical volume on /dev/sdb.My blacklist is empty, why does it say that dm-0/1/2 are blacklisted?Also, when I run lib/udev/scsi_id --whitelisted --device=/dev manually I got no errors. no output or changes either, though...
Multipath to a logical volume in a staging VM
lvm;vmware;storage;scsi;multipath storage
try this multipathd -k show configOn my system it seems that an empty blacklist is ignored and it contains, in addition to vendors blacklisted devices, these devnodes paterns:devnode ^(ram|raw|loop|fd|md|dm-|sr|scd|st)[0-9]*devnode ^hd[a-z]devnode ^dcssblk[0-9]*It matches dm- you could try to add the dm-1, dm-2 ..  devnodes into the blacklist exception. I never tried. I don't know the impact if you put an exception on a multipath dm file for instance. 