5ae40caa6d
tcp_mem defaults to 9% of total memory. ScyllaDB defaults to 93%. The sum is more than 100%. Fix by tuning tcp_mem to 3% of total memory. Fixes https://scylladb.atlassian.net/browse/SCYLLADB-734 Closes scylladb/scylladb#28700
57 lines
1.9 KiB
Bash
57 lines
1.9 KiB
Bash
#!/bin/bash -e
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#
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# Copyright (C) 2023-present ScyllaDB
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#
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#
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# SPDX-License-Identifier: LicenseRef-ScyllaDB-Source-Available-1.0
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#
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trap 'echo "error $? in $0 line $LINENO"' ERR
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version_ge() {
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[ "$2" = "`echo -e "$1\n$2" | sort -V | head -n1`" ]
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}
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KERNEL_VER=$(uname -r)
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if ! version_ge $KERNEL_VER 5.8; then
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# On older kernel environment, we have to relax perf_event_paranoid setting
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# since there is no CAP_PERFMON.
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PERF_EVENT_PARANOID=1
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elif [ $(cat /proc/sys/kernel/perf_event_paranoid) -ge 3 ]; then
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# On Debian/Ubuntu, it deny access from non-root even with CAP_PERFMON
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# It requires to set perf_event_paranoid=2 to use CAP_PERFMON with non-root
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PERF_EVENT_PARANOID=2
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fi
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if [ -n "$PERF_EVENT_PARANOID" ]; then
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cat << EOS > /etc/sysctl.d/99-scylla-perfevent.conf
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kernel.perf_event_paranoid = $PERF_EVENT_PARANOID
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EOS
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sysctl -p /etc/sysctl.d/99-scylla-perfevent.conf
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fi
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# Tune tcp_mem to max out at 3% of total system memory.
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# Seastar defaults to allocating 93% of physical memory. The kernel's default
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# allocation for TCP is ~9%. This adds up to 102%. Reduce the TCP allocation
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# to 3% to avoid OOM.
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PAGE_SIZE=$(getconf PAGE_SIZE)
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TOTAL_MEM_KB=$(sed -n 's/^MemTotal:[[:space:]]*\([0-9]*\).*/\1/p' /proc/meminfo)
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TOTAL_MEM_BYTES=$((TOTAL_MEM_KB * 1024))
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TCP_MEM_MAX=$((TOTAL_MEM_BYTES * 3 / 100))
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TCP_MEM_MAX_PAGES=$((TCP_MEM_MAX / PAGE_SIZE))
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TCP_MEM_MID_PAGES=$((TCP_MEM_MAX * 2 / 3 / PAGE_SIZE))
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TCP_MEM_MIN_PAGES=$((TCP_MEM_MAX / 2 / PAGE_SIZE))
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cat << EOS > /etc/sysctl.d/99-scylla-tcp.conf
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# Scylla: limit TCP memory to 3% of total system memory
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net.ipv4.tcp_mem = $TCP_MEM_MIN_PAGES $TCP_MEM_MID_PAGES $TCP_MEM_MAX_PAGES
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EOS
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sysctl -p /etc/sysctl.d/99-scylla-tcp.conf || :
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if [ ! -d /run/systemd/system ]; then
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exit 0
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fi
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systemctl --system daemon-reload >/dev/null || true
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systemctl --system enable --now scylla-tune-sched.service || true
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