Messages in this thread | | | Date | Wed, 2 Sep 2015 16:12:23 +0200 | From | Dick Streefland <> | Subject | Re: Unexpected slow block device write IO performance compared to uncached, unsynced direct IO using stock kernels |
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On Tuesday 2015-09-01 11:15, Dick Streefland wrote: | I'm seeing this as well here on a number of new Dell Optiplex 7020 | machines and one older Optiplex 780, all with 8GB RAM and running | Ubuntu 14.04 in 32-bit mode.
It turned out that the dirty thresholds in /proc/vmstat became zero:
nr_dirty_threshold 0 nr_dirty_background_threshold 0
A workaround is:
# sysctl vm.highmem_is_dirtyable=1
-- Dick
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