Remote Mirror (SNDR/RDC), creates a network based mirror between two raw devices. When replicating, writes occur on the Primary Host's device no writes occur on the secondary host. When logging, writes may occur on either side, and are tracked through bitmaps.
||Contains primary device. All commands that manipulate the SNDR-set occur here after the set is enabled.
||Contains secondary device. The only command run here is the "enable" command, when the set is first created
||A bitmap. There is a bitmap for both primary and secondary devices. Bitmap becomes active when the SNDR-set goes into a "logging" state. Each bitmap tracks changes in the associated device when in "logging" mode.
||The relationship of:
Primary Host, Primary Device, Primary Bitmap
Secondary Host, Secondary Device, Secondary Bitmap
# pkginfo -x SUNWrdcr
What packages installed?
||SUNWspuni SUNWscm SUNWspsv SUNWrdcr SUNWrdcu
||SUNWscmr SUNWscmu SUNWspsvr SUNWspsvu SUNWrdcr SUNWrdcu
||rdcd and rdcsyncd
||sndrd and sndrsyncd
What drivers loaded?
# modinfo | egrep "(nskern | sdbc | nsctl | rdc | sv | iidev)"
SNDR comes up before DNS, NIS, and NIS+. The /etc/nssitch.conf should point to files for hosts and services. Only hosts that are in use by SNDR need be identified in the /etc/hosts table.
||sndradm is equiivalent to rdcadm which is found in the same directory
||manipulates the data services configuration location
||manipulates sv driver layer
||shows statistics and state of SNDR-set
sndradm commands can be substituded for
rdcadm commands for 2.x version of the software.