On 9/21/19 10:59 AM, Alkis Georgopoulos wrote:
I.e. the problem probably is that when NFS_MAX_READAHEAD=15 was implemented, rsize was 512k; now that rsize=1M, this results in readaheads of 15M, which cause all the traffic and lags.
I filed a bug report for this: https://bugzilla.kernel.org/show_bug.cgi?id=204939 A quick work around is to run on the clients, after the NFS mounts: for f in $(awk '/^v[0-9]/ { print $4 }' < /proc/fs/nfsfs/volumes); do echo 4 > /sys/devices/virtual/bdi/$f/read_ahead_kb done Btw the mail title is wrong, the workaround above causes the netboot traffic to drop from e.g. 1160MB to 221MB in any network speed; it was just more observable in lower speeds. Thank you very much, Alkis Georgopoulos
