RDAC ADT AVT HostType What are that ?
I decide to write this article after start to introduce DS3400 to IBM SVC
I already have DS5000 series storage before and do not have any problem to introduce SVC and no knowledge about ADT/AVT/HostTypeOptions 🙂 what a pity !
After search tens of article and page finally find out a perfect document written by Chinese from IBM, really surprised but congratulation ! You can find the link end of the article
Logical Drives, you can call it as a LUN, which hosts get it as raw space
Controller Ownership, if you are using dual controller systems each created LUNs/Logical drives I/O assigned/shared different controllers for balance. Controller of LUN which do I/O is owner of that LUN.
AVT (Auto Volume Transfer) also referred to as the Auto Disk Transfer, its driver-level failover, its not depend controller-level.
RDAC (Redundant Disk Array Controller), its multipathing software and provide controller redundancy, if one of controller goes down all I/O request directly forwarded to other controller. Some OS do not use RDAC for example Windows, its have own Multipathing software which generally called Native MPIO.
AVT with RDAC, AVT help that logical drive/LUN really switch or sure to secondary controller ready to handle I/O of LUN if Primary controller goes down
HostType (Linux,IBM TS SAN VCE,AIX,HP-UX)
if you want to enable or disable AVT pls use such commends from your DS Storage Manager, choose storage and from Tools menu , select execute script
Execute below is your hosttype selected Linux ;
show controller [a] HostNVSRAMBYTE [5,0x24];
You can change first digit (which is 5 in this example), pls check the pdf to find out related index numbers ” 4.3. How to enable and disable AVT ”
You can see ADT option with script below
show storageSubsystem hostTypeTable;
Pls be careful upgrade times or first installation times , different series DS storages and different versions of firmwares can have different AVT option for same type of host, this is what i see on my systems .
Hope this article summaries many things ..