[Pvfs2-developers] Distribution by hostname
Bradley W Settlemyer
bradles at parl.clemson.edu
Tue Oct 10 15:21:18 EDT 2006
Sam Lang wrote:
>> How about just add PVFS_sys_dist_get_IO_server_aliases() and
>> PVFS_sys_dist_set_IO_server_mapping(). Under the hood each
>> distribution orders the IO servers it'll use according to the
>> mapping then does business as usual. This instead of the random
>> starting point and sequential ordering used now.
> What are the benefits of those functions over something like:
> PVFS_sys_dist_set_param(..., "io-server-mapping", &server_map);
> I dislike the idea of adding interfaces that won't get much use, esp if
> we already have a generic mechanism for doing the same.
Just so we're all clear on what was intended with that interface, the
idea is that distributions can overload the behaviour of the underlying
For example, in the default provided functions, I checked the data for
overrun of the distribution data type, but it doesn't have any support
for an underfilled data type (for example, if an int is set into an
int64, that's probably going to lead to 32 bits of random junk in the
distribution parameter). But that will work fine (though perhaps
precariously) for the default simple-stripe distribution.
The varstrip guys provided a parameter setter that parsed some a string
format. So the current model is that each distribution provides its own
string format. I'm not sure whether that's really the best approach or not.
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