From 41c4d57e5b3c9fcf8ce6937bc5f9c49a92742ee4 Mon Sep 17 00:00:00 2001 From: Aurelien Jarno Date: Fri, 11 Aug 2017 23:40:50 +0200 Subject: [PATCH] ganeti: optimized DRBD parameters --- input/howto/install-ganeti.creole | 15 +++++++++++++++ 1 file changed, 15 insertions(+) diff --git a/input/howto/install-ganeti.creole b/input/howto/install-ganeti.creole index e499613..2f21981 100644 --- a/input/howto/install-ganeti.creole +++ b/input/howto/install-ganeti.creole @@ -468,6 +468,21 @@ Order is important, or else things get very, very confused and the world needs a gnt-cluster command "echo 1 > /sys/bus/pci/devices/0000:0e:00.0/cciss0/rescan" }}} + +=== DRBD optimization === + +The default DRBD parameters are not really optimized, which means very slow (re)syncing. The +following commands might help to make it faster. Of course the max speed can be increased if +both the network and disk speed allow that. + +{{{ + gnt-cluster modify -D drbd:net-custom="--max-buffers 36k --sndbuf-size 1024k --rcvbuf-size 2048k" + gnt-cluster modify -D drbd:c-min-rate=32768 + gnt-cluster modify -D drbd:c-max-rate=98304 + gnt-cluster modify -D drbd:resync-rate=98304 +}}} + + === Change the CPU type === Modern processors come with a wide variety of additional instruction sets (SSE, AES-NI, etc.) which vary from processor to processor, but can greatly improve the performance depending on the workload. Ganeti and QEMU default to a compatible subset of cpu features called qemu64, so that if the host processor is changed, or a live migration is performed, the guest will see its CPUfeatures unchanged. This is great for compatibility but comes at a performance cost. -- 2.20.1