Don Cragun wrote:
> On Wed, 26 Aug 2009 16:21:02 -0700 (PDT), John Forte wrote:
> ... ... ...
>> 4.2 stmfSetAluaState
>>
>> NAME
>> stmfSetAluaState
>>
>> SYNOPSIS
>> cc [ flag... ] file... -lstmf [ library... ]
>> #include <libstmf.h>
>>
>> int stmfSetAluaState(boolean_t enabled, uint8_t node)
>>
>> PARAMETERS
>> enabled B_TRUE when enabling ALUA mode
>> B_FALSE when disabling ALUA mode
>
> I'm having trouble understanding what is going on here. Should "mode"
> in the above two lines be "node"?
No, but the word "mode" could easily be replaced by "state" and perhaps
should.
>
>>
>> node Must be the value 0 or 1
>>
>> DESCRIPTION
>> The stmfSetAluaState() function sets the Asymmetric Logical Unit
>> Access
>> State (ALUA) mode for STMF. When enabled is set to B_FALSE, node
>> is ignored,
>> otherwise, node must be set to 0 or 1. The node setting must be
>> different
>> for each node in a paired config. This should be called only
>> after the
>> STMF proxy door service has been initialized(See
>> stmfInitProxyDoor(3STMF)).
>> When the ALUA state is enabled, all STMF logical units will be
>> registered on the peer node as standby logical units. The standby
>> logical
>> units can then be exported to any SCSI initiator using the existing
>> mechanisms in STMF, stmfAddViewEntry(3STMF) or the add-view
>> subcommand of stmfadm(1M). Note: If ALUA mode is already enabled,
>> it is valid to call this interface again with enabled set to B_TRUE.
>> This action would result in a re-initialization of the ALUA mode.
>> This
>> can be used during recovery of a failed peer node.
>
> According to the Note above, it is not an error to call
> stmfSetAluaState(B_TRUE, node) to reinitialize node if had it previously
> been enabled.
Correct.
>
>>
>> RETURN VALUES
>>
>> The following values are returned:
>>
>> STMF_ERROR_INVALID_ARG Either enabled or node was
>> incorrectly set.
>>
>> STMF_STATUS_SUCCESS The API call was successful
>
> According to the above two lines, stmfSetAluaState() is supposed to
> return STMF_ERROR_INVALID_ARG (because it was enabled) and
> STMF_STATUS_SUCCESS (if it successfully reinitializes node)???
I don't think it says that. STMF_ERROR_INVALID_ARG would be returned if
node was neither 0 or 1.
Perhaps it would be clearer if it was:
RETURN VALUES
The following values are returned:
STMF_ERROR_INVALID_ARG Either "enabled" or "node" was
incorrectly set.
?
>
> ... ... ...
>>
>> 4.3 stmfGetAluaState
>>
>> NAME
>> stmfGetAluaState
>>
>> SYNOPSIS
>> cc [ flag... ] file... -lstmf [ library... ]
>> #include <libstmf.h>
>>
>> int stmfGetAluaState(boolean_t *enabled, uint8_t *node)
>>
>> PARAMETERS
>> enabled set to B_TRUE or B_FALSE on success
>>
>> node set to 0 or 1 on success
>>
>> DESCRIPTION
>> The stmfGetAluaState() function returns the Asymmetric Logical
>> Unit Access
>> State (ALUA) mode for STMF along with the node setting.
>>
>> RETURN VALUES
>>
>> The following values are returned:
>>
>> STMF_ERROR_INVALID_ARG Either enabled or node was NULL.
>>
>> STMF_STATUS_SUCCESS The API call was successful
>
> So, if I call stmfSetAluaState(B_TRUE, 0) and stmfSetAluaState(B_TRUE,
> 1) and then call stmfGetAluaState(&state, &node) what is it supposed to
> do?
Return the last node id set, which in this case would be 1 along with a
state of B_TRUE.
> On which node is it going to report? Since both nodes have been
> enabled, it says that it is going to return STMF_ERROR_INVALID_ARG.
STMF_ERROR_INVALID_ARG is only returned when the arguments are invalid.
As long as "enabled" is B_TRUE or B_FALSE and "node" is either 0 or 1,
that error would not be returned.
To make this clear, "node" is just an identifier for the stmf instance
on which the set ALUA state is executed. It isn't a target for the
execution of the set ALUA state, i.e. the set is not setting the state
for node 0 or node 1, it's setting the state AND setting the node
identifier to 0 or 1.
> But if it successfully sets state and node, it also says it will return
> STMF_STATUS_SUCCESS???
Yes, it's just another state change.
- John
