Disk adapter port connection

DA's are similar to the FA's.  It has two ports behind one processor that runs the fiber protocol over a copper cable.  A cable is run from the back end adapter to the first DAE primary port.  Any DAE beyond that is cabled in a manner just like the Clariion; expansion port to primary port until the end of the loop.  Each DAE contains two LCC (link control cards) where the cable connects.

This is from a comparison document of DMX-4 to V-Max:  Max Drives: 1900. On RPQ: 2400 max

The DMX-4 can have 8 physical DA cards each has 4 processers with two loops behind each processor.

Try not to think of it as drives per port, but per loop.  There are 8 loops on a DA pair, and we allow up to 75 drives per loop.  So 600 drives per DA pair in DMX, 2400 maximum in a DMX4500.    In V-Max it is a little different.  We support up to 2400 drives in an eight engine configuration, but the first 4 engines have 960 drives and the 2nd 4 engines have 1440 drives.  We just announced support for a 4 engine config with 2400 drives, but it won't expand beyond 4 engines.

There is a physical planning guide available for the DMX-4 with the accepted configurations for the DMX-4 series.  You cannot simply look at the number of drive that a director pair can support in a full box configuration versus only have one director pair.

In your configuration you have 2 DA's which are in slots 1 and 16.  These directors support the bottom left quadrant of disks in the bay.  Once you get to 240 physical drives it appears that the next step is to add in the director pair 2 and 15 to support the top left quadrant.

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OK , so eight port on each DA ,  total 16 port available in a pair which can be connected to 8 shelfs ( one port from each director ) .

So how can we calculate the max drive and min. drive that can be connected in case of 2 DA ( one pair only)

as per Doc it is  Min 96  and 240 max

How this calculation happen ??

~ Bipul

Bipul,

     May I ask if the system configuration you have or are thinking about is a DMX-4 950 or a DMX-4 1500 model?  Both have the same number of DA to DAE connections as has been mentioned (8 ports per DA board, 2 per CPU, and the DA pairs are mirrored to each other for redundancy, so essentially they only see 8 fibre channel drive loops); however, as far as expandability and options available to you, they are very different.

     The DMX-4 950 model is an integrated system and drive bay model where the director and cache/memory are placed in a 6-slot chasis (4 for directors: 2 back-end directors, 2 front-end, & 2 mirrored cache boards).  The DMX-4 950 comes with a minimum of 8 DAEs that are placed inside the same bay as the system chassis.  1 port from each DA will connect to each DAE (which provides the redudancy pathing).   Each DAE holds a maximum of 15 physical drives.  So this gets you to the 1st 120 drives.  The second 120 drives (which get you to the max of 240) is done by adding a 2nd bay which contains another 8 DAEs.  These 8 DAEs are connected (as mentioned earlier), through cables to the 8 DAEs in the integrated bay.  This allows each port on the DA to see 2 DAEs rather than 1.  Beyond that, the DMX-4 950 can not upgrade further.

     The DMX-4 1500 model as a minimum is a 2 bay model; one system bay and one drive bay.  It is also has a lot more expandability options in terms of number of drives, directors and memory/cache.  The connections are done the same as explained above in the DMX-4 950.  This will get you 120 drives (with one drive bay).  To get the 240, you add a second drive bay and connect it to the first drive bay.

     Now you may ask, why can't we go beyond 240 drives in both?  We could surely add another set of DAEs, and another, to the DAs until we reach the fibre channel restriction, right?  Sure we could, but then we would need to expand cache/memory for the system to maintain performace, which means we also need to expand the amount of vault capacity.  To expand vault capacity, we need more DAs; hence, once you reach 240 drives on a DMX-4 1500, we say to expand drive capacity past that, the system needs to be upgraded to a DMX-4 2500.  This adds another pair of DA boards to the 1500 system and doubles the vaulting capacity, which in turn allows you to expand cache/memory and then allowing to add more disks past 240.

Hope this helps,

PSE Chris

Thanks Quincy.

  So its 8 loops on a DA pair , and 75 drives per loop at max .

i am still with max/min number of drives as mentioned in the doc. 

96 min. and 240 max , what this means , ( from DMX-4 product guide) page 51 table 9

How this works in light of minimum 4 disk and max 15 disk per disk subsystem (shelf)

Thanks

Bipul

Thanks Chris,

                      That do answer my question on 240 max drive  on a DA pair ,  can you also explain  minimum 96 drive  also .. how that is calculated ..

Bipul

Thanks Chris , i got my answers..

Thanks all , who reply to my question

Bipul