Getting error "kernel: blk_rq_check_limits: over max size limit" when changing the max_sectors_kb value on multipath devices or their underlying individual paths

Solution Verified - Updated -

Issue

  • We are receiving the following errors when accessing LUNS.
    This only happens when setting /sys/block/dm-\*/slaves/sd\*/queue/max_sectors_kb to 128.

    Jun 14 14:54:55 server kernel: blk_rq_check_limits: over max size limit.
    Jun 14 14:54:55 server kernel: blk_rq_check_limits: over max size limit.
    

    This does not occur when we leave the max_sectors_kb at 512.
    the error is causing path failures and paths fail over.

  • With kernel-2.6.32-642.el6 and later, there is a slightly different error logged:

    Jun 14 09:33:38 testhost kernel: blk_cloned_rq_check_limits: over max size limit.
    Jun 14 09:33:38 testhost kernel: blk_cloned_rq_check_limits: over max size limit.
    

Environment

  • Red Hat Enterprise Linux 8
  • Red Hat Enterprise Linux 7
  • Red Hat Enterprise Linux 6
  • Red Hat Enterprise Linux 5
  • DM-Multipath

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