Can someone let me know the concept of SSID on VSP?
In order to understand why there are control units and SSID's on a VSP even for Open Systems you have to take a trip back in time to the Mainframe world of parallel channels and ESCON channels.
The original control unit was a physical beast and was called a 3990 with actual physical 3390 disk drives
Over time the parallel channels were replaced by ESCON channels which required a SSID in order to address the Control Units
These Physical Control units were replaced by Virtual Control Units in a IBM Shark with the advent of modern storage arrays.
On a RAID400/500/600/700 there is a setting for CU Emulation which is normally set to shark emulation i.e the Mainframe thinks it is dealing with a IBM Shark. There are also Mainframe drive emulations like 3390 etc.
So when you install RAID Groups in a USP/USPV/VSP you assign a emulation to the LDEVs on the RAID group which could be 3390 etc.
At the same time you have to pick a CU:LDEV address to assign to the LDEV itself. Every Control Unit has to be assigned a SSID in order for the Mainframe to address the devices. Note that the Control Units are not Physical anymore but virtual. If the VSP is going to be put into use for Open Systems only then you can pick any valid hex number [range] for the SSID. If it is going to be used for Mainframes then you have to pick ones that the Mainframe guys tell you to set it to.
Since a VSP caters to both Open Systems as well as to Mainframes, in the open systems world a Control Unit Number with a SSID is just that a logical container for LDEVs. In the mainframe world a SSID is how the 3390 etc devices in the Control Unit are addressed.
SSID - Sub System ID.
For each LDEV created from the RG a unique SSID number is assigned.
Thanks Kamal..Congrats for joining iGate!
what is the difference between VSP V1 and VSP V2??
i am hearing this term now days saying VSP Version2...
Version2 is nothing but you will have some advancements in the features + the cache capacity is more, for example a single chassis supports 512GB of cache in V2 and dual chassis supports 1024 GB.
I was told by more experienced colleagues that SSIDs are only used for mainframe hosts. It is configurable in the Service Processor's Install panel during the creation of a new parity group.
Many thanks. Here we don't have control over SVP, HDS is configuring raid groups for us. Last couple of months I have sent mutiple post to understand about emulation,SSID,CU concepts. Now the concept is clear for me. Thanks again.
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