Gitweb: http://git.fedorahosted.org/git/?p=lvm2.git;a=commitdiff;h=b48ff3b94e7cd771b... Commit: b48ff3b94e7cd771bbaf42f38b546054d02bc0f2 Parent: 5e25bca1a98f2376b94904a2e220a3e2f68923ad Author: David Teigland teigland@redhat.com AuthorDate: Thu Mar 5 12:12:42 2015 -0600 Committer: David Teigland teigland@redhat.com CommitterDate: Thu Mar 5 12:12:42 2015 -0600

man: add info to lvmsystemid

about losing access to a VG if lvm is downgraded to an earlier version. --- man/lvmsystemid.7.in | 21 ++++++++++++++------- 1 files changed, 14 insertions(+), 7 deletions(-)

diff --git a/man/lvmsystemid.7.in b/man/lvmsystemid.7.in index 0881b1e..76b0e83 100644 --- a/man/lvmsystemid.7.in +++ b/man/lvmsystemid.7.in @@ -42,13 +42,7 @@ maximum length of a system_id is 128 characters.

To benefit fully from system_id, all hosts must have system_id set, and VGs must have system_id set. A VG on shared storage can be damaged or -destroyed in the following cases which the user must be careful to avoid: - -.IP [bu] 2 -A host using an old version of lvm without the system_id feature will not -recognize the system_id of other hosts' VGs. VGs with a new system_id -are nominally protected from old versions of lvm by appearing to be -read-only to the old versions. +destroyed in some cases which the user must be careful to avoid.

.IP [bu] 2 A VG without a system_id can be used without restriction from any host, @@ -73,6 +67,19 @@ operations and corrupting the PVs. See the .B orphans section for more information.

+.IP [bu] 2 +A host using an old version of lvm without the system_id feature will not +recognize a new system_id in VGs from other hosts. Even though the old +version of lvm is not blocked from reading a VG with a system_id, it is +blocked from writing to the VG (or its LVs). The new system_id changes +the write mode of a VG, making it appear read-only to previous lvm +versions. + +This also means that if a host downgrades its version of lvm, it would +lose access to any VGs it had created with a system_id. To avoid this, +the system_id should be removed from VGs before downgrading to an lvm +version without the system_id feature. + .P

.SS Types of VG access