AIX

Sorry for my english.

We have a IBM BLADES JS21. AIX 5.3 update to 6.

Our JS21 has 2 FC (fcs0 and fcs1).

We have one DS4072, one Disk system with 2 controllers and 2 FC by controllers.

This means, all AIX FC see all Disk systems controllers by 2 FC switchs. (one fc two roads)

FC AIX -----> SWITCH A <----- 2 FC Controllers. A1 - B1
FC AIX -----> SWITCH B <----- 2 FC Controllers. A2 - B2

Is it support?. Because I only see one DAR (it is correct because I have only on partition on my Disk System). But I see 4 DAC ( DAC0 - DAC3 ) and I can not configure fault tolerant.

Thanks.

You will need to make use of some multipathing software like powerpath,SDD or IBM MPIO [ it's free ].

AFAIK, powerpath, SDD or MPIO is NOT supported on AIX and the DS4000 Family of products.

Again, AFAIK, the ONLY product supported on AIX and the DS4000 Family of products is --> RDAC. RDAC on AIX provides the pseudo multipathing s/w you need. I use the word pseudo only to suggest it is not really multipathing but more redundant paths, with only one path active to a LUN at any given time.

But the landscape is always changing.... should powerpath, SDD or MPIO every be supported by AIX and the DS4000 Family of products, please correct me & post a link so we can all read about the new support.


Is the DS4072 a typo ? Sorry, never heard of the DS4072. I'll assume what you have is from the DS4000 family of storage products.

Since you have stated you have "darX and dacX" devices installed it appears the RDAC drivers are installed just fine. BTW, no further fault tolerant configuration is needed. RDAC handles it automatically, provided your configraution is correct. BUT, as depicted the above configuration is NOT supported. You might get portions to work, but expect to be plagued with problems.

To convert your configuration to a supported config on AIX, an example of where you need to get to is next:

fcs0 -----> switch A <------ A1 controller
fcs1 -----> switch B <------ B1 controller

To get to this config, "some" of the things you need to do are:

Code:

1.  rmdev -d -l hdiskX     # remove ALL hdisk devices that are LUNs on your DS4000
                           # this assumes your rootvg is on an internal disk on your JS21
2.  rmdev -d -l dacX       # remove ALL dac devices
3.  rmdev -d -l darX       # remove ALL dar devices                           
4.  permanently, disconnect the fibre cable going to the A2 controller
5.  permanently, disconnect the fibre cable going to the B2 controller
6.  move the fibre cable from B1 controller and attach it to switch B
7.  verify (& correct if necessary) the LUN masking in the DS4000 so that your AIX host is properly known to the DS4000.
    a.k.a. allocate the LUN(s) to the AIX host
8.  re-boot AIX (or re-run "cfgmgr")

Alternatively, for steps 4 & 5, implement zoning in your switches so that AIX "never" sees the A2 & B2 controllers.

For reference material, I'd suggest you read Chapter 11 of the following IBM redbook --> http://www.redbooks.ibm.com/abstract...6363.html?Open

When set up correctly, you'll see only the following devices:

Code:

dar0
dac0   --- to the A1 controller
dac1   --- to the B1 controller
hdiskA --- to the 1st LUN
hdiskB --- to the 2nd LUN
hdiskC --- to the 3rd LUN
hdiskD --- to the 4th LUN
etc.

In your case, if your AIX system sees extra "darX or dacX" devices or extra "hdiskX" devices, there's an error in your config & you'll need to go back & debug your installation.

Hope this helps.

Is that documented anywhere by IBM that DS4000 does not support powerpath,SDD or MPIO ?

AFAIK, there is no documentation, either way, indicating support or no support for powerpath, SDD, or MPIO on AIX with DS4000 Family of products.

Without a "positive" statement of support from IBM, I can only infer "no" support.