Re: [dm-devel] Re: [RFD] BIO_RW_BARRIER - what it means for devices, filesystems, and dm/md.

[Valdis . Kletnieks]

On Tue, 10 Jul 2007 14:39:41 EDT, Ric Wheeler said:

> All of the high end arrays have non-volatile cache (read, on power loss, it is a 
> promise that it will get all of your data out to permanent storage). You don't 
> need to ask this kind of array to drain the cache. In fact, it might just ignore 
> you if you send it that kind of request ;-)

OK, I'll bite - how does the kernel know whether the other end of that
fiberchannel cable is attached to a DMX-3 or to some no-name product that
may not have the same assurances?  Is there a "I'm a high-end array" bit
in the sense data that I'm unaware of?

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