On Tue, 9 Jan 2007, Neil Brown wrote: > Imagine a machine with lots of memory - say 100Gig.
i've had these problems on machines as "small" as 8GiB. the real problem is that the kernel will let millions of potential (write) IO ops stack up for a device which can handle only mere 100s of IOs per second. (and i'm not convinced it does the IOs in a sane order when it has millions to choose from) replacing the percentage based dirty_ratio / dirty_background_ratio with sane kibibyte units is a good fix... but i'm not sure it's sufficient. it seems like the "flow control" mechanism (i.e. dirty_ratio) should be on a device basis... try running doug ledford'd memtest.sh on an 8GiB box with a single disk, let it go a few minutes then ^C and type "sync". i've had to wait 10 minutes (2.6.18 with default vm settings). it makes it hard to guarantee a box can shutdown quickly -- nasty for setting up UPS on-battery timeouts for example. -dean - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/