>On 9/11/06, Fu Zhi-jun <Zhijun.Fu at sun.com> wrote:
>> Hi,all,
>>
>> Recently I met a problem in using smf.
>> I used "svccfg -s ${FMRI} setprop config/$SERVICE_ENABLED = true" to
>> enable a service,and then used "svcprop -p config/$SERVICE_ENABLED
>> $FMRI" to retrieve the value to judge whether the service is enabled. To
>> my surprise, svcprop told me the service is 'disabled'.
>> Later, I learned from others that svccfg operates on 'current' set, and
>> svcprop retrieves value from 'running" snapshot, so I need to use
>> "svcadm refresh $FMRI" to copy the value to running set, or use '-c' to
>> let svcprop retrieve value from 'current' set.
>>
>> Then my question is, why we need the running snapshot? Isn't it easier
>> to use only the current set other than syncing between the two sets?
>
>At least for scripting, it will be disruptive to the service if SMF
>syncs for every in-transit svccfg invocations.
There are several other reasons:
- the requirement of doing "svcadm refresh" after modifying
properties allow you to reconfigure the services without worrying
about the system behaving strangely when only a part of the
properties have been updated
- the "current" repository keep tracks of services coming on-line;
in general the on-disk repository does not need to be written
when booting
- the "current" repository allows for temporary disabling of
services (disable until next reboot)
Casper
