[Beowulf] Lustre failover

Mark Hahn hahn at mcmaster.ca
Wed Sep 10 07:34:45 PDT 2008

>> active/active seems strange to me - it implies that the bottleneck
>> is the OSS (OST server), rather than the disk itself.  and a/a means
>> each OSS has to do more locking for the shared disk, which would seem
>> to make the problem worse...
> No, you can do active/active with several systems
>      Raid1
>     /     \
> OSS1        OSS2
>    \      /
>     Raid2
> (Raid1 and Raid2 are hardware raid systems).
> Now OSS1 will primarily serve Raid1 and OSS2 will primarily serve Raid2. So

yes, I know - that's how HP SFS is set up.  the OP was talking active-active,
though, meaning that IO at any instant can go to either OSS and still make 
it onto a particular raid.  otherwise it's active/passive, what SFS does.

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