Red Hat Bugzilla – Bug 155427
kernel dm-multipath: How to handle IO barriers?
Last modified: 2007-11-30 17:11:04 EST
How should IO barriers be handled - should they be short-circuited and disabled
in the mapping function directly, do we want to support them - which would
probably involve sending them down all paths -, or is there another option...?
I'm tending towards short circuiting them.
Created attachment 113406 [details]
Make dm-multipath report barriers as "not supported"
We need IO barriers which don't carry any data; then we have to send them down
all the paths that might have unsynced IO on them, leading to fun interactions
with priority groups, switch_pg when paths haven't failed etc.
Until then they don't work so not supported.
Added to 2.6.12-rc2-udm1.