Strict replication
Use mmchfs -K no command to perform disk action for strict replication.
If data or metadata replication is enabled, and the status of an
existing disk changes so that the disk is no longer available for
block allocation (if strict replication is enforced), you may receive
an errno of ENOSPC when you create or append
data to an existing file. A disk becomes unavailable for new block
allocation if it is being deleted, replaced, or it has been suspended.
If you need to delete, replace, or suspend a disk, and you need to
write new data while the disk is offline, you can disable strict replication
by issuing the mmchfs -K no command before
you perform the disk action. However, data written while replication
is disabled will not be replicated properly. Therefore, after you
perform the disk action, you must re-enable strict replication by
issuing the mmchfs -K command with the original
value of the -K option (always or whenpossible)
and then run the mmrestripefs -r command.
To determine if a disk has strict replication enforced, issue the mmlsfs
-K command.
Note: A disk in a down state
that has not been explicitly suspended is still available for block
allocation, and thus a spontaneous disk failure will not result in
application I/O requests failing with ENOSPC. While new blocks will
be allocated on such a disk, nothing will actually be written to the
disk until its availability changes to up following
an mmchdisk start command. Missing replica
updates that took place while the disk was down will be performed
when mmchdisk start runs.