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On Sat, 16 Jun 2007, Neil Brown wrote: > It would be possible to have a 'this is not initialised' flag on the > array, and if that is not set, always do a reconstruct-write rather > than a read-modify-write. But the first time you have an unclean > shutdown you are going to resync all the parity anyway (unless you > have a bitmap....) so you may as well resync at the start. > > And why is it such a big deal anyway? The initial resync doesn't stop > you from using the array. I guess if you wanted to put an array into > production instantly and couldn't afford any slowdown due to resync, > then you might want to skip the initial resync.... but is that really > likely? in my case it takes 2+ days to resync the array before I can do any performance testing with it. for some reason it's only doing the rebuild at ~5M/sec (even though I've increased the min and max rebuild speeds and a dd to the array seems to be ~44M/sec, even during the rebuild) I want to test several configurations, from a 45 disk raid6 to a 45 disk raid0. at 2-3 days per test (or longer, depending on the tests) this becomes a very slow process. also, when a rebuild is slow enough (and has enough of a performance impact) it's not uncommon to want to operate in degraded mode just long enought oget to a maintinance window and then recreate the array and reload from backup. David Lang - 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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