Messages in this thread | | | Date | Tue, 01 Aug 2006 23:52:06 -0400 | From | David Masover <> | Subject | Re: Solaris ZFS on Linux [Was: Re: the " 'official' point of view"expressed by kernelnewbies.org regarding reiser4 inclusion] |
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Ian Stirling wrote: > David Masover wrote: >> David Lang wrote: >> >>> On Mon, 31 Jul 2006, David Masover wrote: >>> >>>> Oh, I'm curious -- do hard drives ever carry enough >>>> battery/capacitance to cover their caches? It doesn't seem like it >>>> would be that hard/expensive, and if it is done that way, then I >>>> think it's valid to leave them on. You could just say that other >>>> filesystems aren't taking as much advantage of newer drive features >>>> as Reiser :P >>> >>> >>> there are no drives that have the ability to flush their cache after >>> they loose power. >> >> >> Aha, so back to the usual argument: UPS! It takes a fraction of a >> second to flush that cache. > > You probably don't actually want to flush the cache - but to write > to a journal. > 16M of cache - split into 32000 writes to single sectors spread over > the disk could well take several minutes to write. Slapping it onto > a journal would take well under .2 seconds. > That's a non-trivial amount of storage though - 3J or so, 40mF@12V - > a moderately large/expensive capacitor.
Before we get ahead of ourselves, remember: ~$200 buys you a huge amount of battery storage. We're talking several minutes for several boxes, at the very least -- more like 10 minutes.
But yes, a journal or a software suspend. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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