Valdis.Kletnieks@xxxxxx wrote: > 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? Well, the array just has to tell the kernel that it doesn't to write back caching. The kernel automatically selects ORDERED_DRAIN in such case. -- tejun -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel
