Escalated to Bugzilla from IssueTracker
Event posted on 07-08-2010 05:23am CST by jnomura
Cloning from IT 378094 / BZ 518982 which was about dracut and multipath
NEC's concerns about blacklist methods in RHEL 6:
multipath.conf can be written in 2 ways:
1) blacklist everything and add specific devices to blacklist_exceptions
2) blacklist specific devices
RHEL 5 used method 1, but it appears RHEL 6 is switching to method 2.
Both look same but if you add a local disk to the system after
installation, for example, (2) will result in treating the new disk as a
multipath device, but (1) will not. The result with (2) would be
confusing for customers, so RHEL5 anaconda took the approach (1).
Email response from Peter Jones (anaconda engineering):
Well, he's not entirely correct - we're not using an "empty"
blacklist; we're listing certain classes of things as blacklisted by
default - we're blacklisting all SATA devices, for example, which is
how local disks will typically be attached.
That being said, it really would be better if /sbin/multipath didn't
try to create multipath devices when there's only one path, but
that's an issue for the multipath maintainers, not for the installer.
I would be happy to accept a patch to anaconda to create a
multipath.conf at the _end_ of installation which creates
blacklist_exceptions entries for each identified multipath device
and makes a generic blacklist for everything else, though it's of
questionable benefit given the blacklisting of classes of devices
I mentioned above. It's impractical to use this method of operation,
See attached patch from NEC:
This event sent from IssueTracker by dwu [Support Engineering Group]
Created attachment 430245 [details]
Should be fixed in anaconda-13.21.59-1 .
[root@dhcp70-190 ~]# multipath -ll
mpatha (3600a0b800034867a000005cd47d96f66) dm-0 SGI,IS400
size=339G features='3 queue_if_no_path pg_init_retries 50' hwhandler='1 rdac' wp=rw
|-+- policy='round-robin 0' prio=6 status=active
| `- 1:0:0:3 sdb 8:16 active ready running
`-+- policy='round-robin 0' prio=1 status=enabled
`- 0:0:0:3 sda 8:0 active ghost running
[root@dhcp70-190 ~]# cat /etc/multipath.conf
# multipath.conf written by anaconda
Tested on build RHEL6.0-20100811.2 / x86_64 with anaconda-13.21.74-1.el6.
Moving to VERIFIED.
Red Hat Enterprise Linux 6.0 is now available and should resolve
the problem described in this bug report. This report is therefore being closed
with a resolution of CURRENTRELEASE. You may reopen this bug report if the
solution does not work for you.