Some storage arrays implement the PREF (preference) bit, which enables an array to specify which SP is the preferred owner of a given LUN. This allows the storage administrator to spread the LUNs over both SPs (for example, even LUNs on one SP and odd LUNs on the other SP). Whenever the need arises to shut down one of the SPs, the LUNs owned by that SP (say SPA) get transferred to the surviving nonpreferred SP (SPB). As a result, the AAS of the port group on SPB is changed to AO. ALUA followover honors this change and sends the next I/O intended for the transferred LUNs to the port group on SPB. When SPA is brought back online, the LUNs it used to own get transferred back to it. This reverses the changes done earlier, and the AAS of the port group on SPA is set to AO for the transferred LUNs. Conversely, the AAS of the port group on SPB, which no longer owns the LUNs, is changed to ANO. Again, ALUA followover honors this change and switches the I/O back to the port group on SPA. This is the default behavior of ALUA-capable HP EVA storage arrays.

Determining Device ALUA Arrangement

ESXi 6 host configuration that enables use of ALUA devices is a PSA component in the form of a SATP (see Chapter 5, “vSphere Pluggable Storage Architecture [PSA]”). [Read more…]

Charlene Perera and you will Patrick Miller

Charlene battled to share her thoughts, Patrick wished to has a good amount of deep and you can meaningfuls. Their relationships checked very top to bottom throughout the tell you, nonetheless it is an enjoyable amaze to see him or her deciding to stay with her at the conclusion of this new try.

Sadly, their love don’t bloom any more and the partners decided to wade the separate suggests. Pat shared an excellent heartfelt message from assistance to possess Charlene on Instagram, and they proceeded so you’re able to get back because the nearest and dearest. [Read more…]