The fresh active nature of multipathing and you may failover necessitates the flexibility out-of dealing with and you can controlling a keen ALUA TPG’s AAS

The reverse is true for TPG thereupon try, it’s AO for LUN dos and ANO getting LUN 1.

To your specific productive/couch potato ALUA-capable arrays, you are able to see port groups which have “Standby” AAS in lieu of “ANO” on the low-manager SP.

Asymmetric Supply Condition

Ports in an ALUA TPG can be in the same AAS at all times with respect to a given LUN. The TPG’s AAS are reported to the initiators in response to the Declaration TPGS command. The TPG descriptor is reported in byte 1 of that response.

Transitioning-This new TPG AAS is in the means of altering from 1 county to a different. Particularly, should your SP regarding an enthusiastic AO TPG is being rebooted otherwise is actually taken off-line, or if perhaps the fresh SAN (space for storing circle) admin yourself transfers LUN possession (on the EMC CLARiiON, this will be called trespass), the brand new AAS of one’s TPG toward choice SP transform so you’re able to AO. Although this procedure try ongoing, the fresh TPG AAS is actually transitioning.

While the TPG is in this state, receiving requests from the initiators return Hectic or a Consider Standing with sense key Perhaps not Ready and ASC (additional sense code) Logical Tool Perhaps not Obtainable or ASYMMETRIC Accessibility County Transition.

Standby-This state is similar to a passive SP in a non-ALUA configuration and on certain ALUA-capable arrays. It returns a Examine Position with sense key Perhaps not Ready.

If TPG is within this AAS, it supports good subset from purchases which accepts in the event it is within AO AAS:

Unavailable-This AAS might be seen if the TPG’s use of brand new LUN is bound as a result of apparatus mistakes or other SCSI unit limits. A TPG in this condition is not able to change so you’re able to AO or ANO

before mistake subsides.

ESXi six sends the fresh new I/O to TPGs which might be from inside the AO AAS, in case they are certainly not readily available, I/O is distributed so you can TPGs that are within the ANO AAS. If for example the storage selection obtains suffered We/O on the TPGs that are inside ANO AAS, the newest array changes this new TPG’s condition so you’re able to AO AAS. Who can make one changes hinges on the fresh ALUA management form out-of this new shop selection (see the 2nd area).

ALUA Government Settings

This is accomplished thru a collection of datingmentor.org/arizona-scottsdale-dating/ instructions and you may answers in order to and you may on stores arrays. These types of sales are listed below:

Query-According to SPC-3, section 6.4.2, in response to this command, an array returns certain pages of the VPD (vital product data) or EVPD (extended vital product data). The inquiry data returned in response to this command includes the TPGS field. If the returned value in that field is nonzero, that device (LUN) supports ALUA. (See Table 6.3, later in this chapter, for the correlation between the value of the TPGS field and AAS management modes.)

Place Address Vent Communities (Put TPGs)-This command requests that the storage array set the AAS of all ports in specified TPGs. For example, a TPG’s AAS can transition from ANO to AO via the Put TPGs command.

Table six.1 ALUA AAS administration modes

Not Supported-The response to the Statement TPGs and Lay TPGs commands is invalid. This means that the storage array does not support ALUA or, in the case of EMC CLARiiON, the initiator records are not configured in a mode that supports ALUA.

Implicit-The array responds to Statement TPGs but not Set TPGs commands. In this case, setting the TPG’s AAS is done only by the storage array.

Explicit-The array responds to both Report TPGs and Set TPGs commands. In this case, setting the TPG’s AAS can be done only by the initiator.