Fredrik Tolf <fred...@dolda2000.com> wrote: > It is worth noting, also, that this seems to be a situation > introduced somewhere between 2.6.26 and 2.6.32, because I started > noticing it when I upgraded from Debian 5.0 to 6.0. I've since tried > it on 3.2.0, 3.5.4 and 3.7.1, and it appears in every version. > However, I can't easily go back and bisect, because the new init > scripts don't support kernels older than 2.6.32, unfortunately.
I'm not sure about Debian-specific changes to the kernel, but in the stock kernel, the dirty*ratios changes could affect you: before 2.6.22 dirty_ratio=40 dirty_background_ratio=10 2.6.22-2.6.29 dirty_ratio=10 dirty_background_ratio=5 2.6.30-... dirty_ratio=20 dirty_background_ratio=10 So try lowering these sysctls to 2.6.26 levels (or lower) and see if that helps. Fwiw, I usually use dirty_ratio=2 dirty_background_ratio=1 on servers with a few gigs of RAM (or appropriately low dirty*bytes values). Lowering dirty*ratio helps servers get more consistent performance under constant I/O pressure and aggressively throttles processes before a large amount of dirty pages becomes a problem (as you've noticed). High dirty*ratio is good for some bursty desktop workloads and some benchmarks, though... ref: commit 07db59bd6b0f279c31044cba6787344f63be87ea ref: commit 1b5e62b42b55c509eea04c3c0f25e42c8b35b564 Heck, on a particularly bad server (2.6.18, pre-dirty_*bytes sysctl) with lots of RAM and horrible disk throughput (~10M/s), I set both dirty_writeback_centisecs and dirty_expire_centisecs to 100 to get acceptable performance for writing HTTP access logs. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
