Which three /etc/snapmirror.conf entries will support synchronous or semi-synchronous SnapMirror?
A.
FilerA:source_vol FilerB:destination_vol visibility_interval = lhr, outstanding
= 3ms, cksum=crc32 sync
B.
FilerA:source_vol FilerB:destination_vol – 0-55/5 * * *
C.
FilerA:source_vol FilerB:destination_vol – sync
D.
FilerA:source_vol FilerB:destination_vol outstanding=3s sync
Explanation:
https://library.netapp.com/ecmdocs/ECMP1196979/html/man5/na_snapmirror.conf.5.html
Each relationship entry of the /etc/snapmirror.conf file is a single line containing space-separated fields.
The entry has this format:
source destination arguments schedule
schedule
This is the schedule used by the destination node for updating the mirror. It informs the SnapMirror scheduler
when transfers will be initiated. The schedule field can contain the word sync to specify fully synchronous
mirroring, semi-sync to specify semi-synchronous mirroring, or a cron-style specification of when to update the
mirror.
visibility_interval
The value for this argument is a number optionally followed by the suffixes: s (seconds), m (minutes) or h
(hours). If a suffix is not specified, value is interpreted as seconds. This argument controls the amount of time
before an automatic snapshot is created on the source volume that is synchronously mirrored. The value is the
number of seconds between automatically created snapshots. The default value is 3 minutes. A small number
here can negatively affect the performance of the mirror. This argument is ignored for asynchronous mirrors.
outstanding (deprecated)
This argument controls the performance versus synchronicity trade-off for synchronous mirrors. The value for
this argument is a number followed by the suffixes: ops (operations), ms (milliseconds) or s (seconds). Setting avalue less than 10s configures the mirror to run in fully synchronous mode. Setting a value greater than or
equal to 10s configures the mirror to run in semi-synchronous mode. This argument is ignored for
asynchronous mirrors. Please note that this is a deprecated option. Use the schedule field to specify the
synchronous mode for the mirror.
cksum This controls which checksum algorithm is used to protect the data transmitted by SnapMirror. Currently
supported values are “none”, “crc32c”, and “crc32c_header_only”. The value “crc32c_header_only” has been
added only for volume SnapMirror and is not supported for synchronous SnapMirror and qtree SnapMirror.