自己的土豆服务器本来配置就不怎么样(4C+2G),装了一堆乱七八糟的东西之后卡的飞起...(Jenkins/Nginx/iRedMail/Typecho...)
逼着我要优化一下了...

[email protected]:~# free -m
              total        used        free      shared  buff/cache   available
Mem:           1994        1709          94          17         190         126
Swap:          2047         283        1764

除了Nginx/iRedMail/MySQL其他也没跑什么东西...看了下内存占用

[email protected]:~# ps aux | head -1;ps aux |grep -v PID |sort -rn -k +4 | head -20
USER       PID %CPU %MEM    VSZ   RSS TTY      STAT START   TIME COMMAND
clamav     525 11.9 41.9 1187216 857852 ?      Ssl  16:15   0:23 /usr/sbin/clamd --foreground=true
amavis    2464  0.2  4.8 167476 99752 ?        S    16:15   0:00 /usr/sbin/amavisd-new (ch1-avail)
amavis    2463  0.2  4.8 167476 99768 ?        S    16:15   0:00 /usr/sbin/amavisd-new (ch1-avail)
amavis    1785  1.3  3.7 167476 77476 ?        Ss   16:15   0:02 /usr/sbin/amavisd-new (master)
mysql      630  0.3  3.2 2700112 67172 ?       Ssl  16:15   0:00 /usr/sbin/mysqld
12000     2710  0.9  2.4  64516 49272 ?        Sl   16:15   0:01 /usr/local/bin/python /usr/local/bin/gunicorn oj.wsgi --user server --group spj --bind 127.0.0.1:8080 --workers 4 --threatter 10000 --max-requests 1000000 --keep-alive 32
12000     2709  0.4  1.8  49108 38628 ?        S    16:15   0:00 /usr/local/bin/python /usr/local/bin/gunicorn oj.wsgi --user server --group spj --bind 127.0.0.1:8080 --workers 4 --threatter 10000 --max-requests 1000000 --keep-alive 32
12000     2708  0.5  1.8  49112 38668 ?        S    16:15   0:00 /usr/local/bin/python /usr/local/bin/gunicorn oj.wsgi --user server --group spj --bind 127.0.0.1:8080 --workers 4 --threatter 10000 --max-requests 1000000 --keep-alive 32
12000     2699  0.5  1.8  49100 38700 ?        S    16:15   0:00 /usr/local/bin/python /usr/local/bin/gunicorn oj.wsgi --user server --group spj --bind 127.0.0.1:8080 --workers 4 --threatter 10000 --max-requests 1000000 --keep-alive 32
root       515  1.1  1.5 1972748 31084 ?       Ssl  16:15   0:02 /usr/bin/dockerd -H fd:// --containerd=/run/containerd/containerd.sock
nobody    2819  0.6  1.5  48360 31632 ?        Sl   16:15   0:01 /usr/local/bin/python /usr/local/bin/dramatiq --path . --processes 4 --threads 4 django_dramatiq.setup django_dramatiq.tas.tasks judge.tasks
nobody    2818  0.7  1.5  48292 31624 ?        Sl   16:15   0:01 /usr/local/bin/python /usr/local/bin/dramatiq --path . --processes 4 --threads 4 django_dramatiq.setup django_dramatiq.tas.tasks judge.tasks
nobody    2817  0.7  1.5  48420 31616 ?        Sl   16:15   0:01 /usr/local/bin/python /usr/local/bin/dramatiq --path . --processes 4 --threads 4 django_dramatiq.setup django_dramatiq.tas.tasks judge.tasks
nobody    2816  0.6  1.5  48216 31620 ?        Sl   16:15   0:01 /usr/local/bin/python /usr/local/bin/dramatiq --path . --processes 4 --threads 4 django_dramatiq.setup django_dramatiq.tas.tasks judge.tasks
root       514  0.7  0.8 1481644 17500 ?       Ssl  16:15   0:01 /usr/bin/containerd
root       509  0.8  0.8 989136 18300 ?        Ssl  16:15   0:01 /usr/bin/python3 /usr/bin/fail2ban-server -xf start
root       501  0.9  0.8 119664 18352 ?        Ssl  16:15   0:01 /usr/bin/v2ray/v2ray -config /etc/v2ray/config.json
root      2495  0.1  0.8  92952 18356 ?        S    16:15   0:00 /usr/bin/python3 /usr/local/bin/gunicorn --workers 8 --threads 8 --error-logfile /log/gunicorn.log --time 600 --bind 0.0.
root      2493  0.1  0.8  92984 18380 ?        S    16:15   0:00 /usr/bin/python3 /usr/local/bin/gunicorn --workers 8 --threads 8 --error-logfile /log/gunicorn.log --time 600 --bind 0.0.
root      2491  0.1  0.8  92948 18376 ?        S    16:15   0:00 /usr/bin/python3 /usr/local/bin/gunicorn --workers 8 --threads 8 --error-logfile /log/gunicorn.log --time 600 --bind 0.0

一个ClamAV吃了800M的内存...而且作用还不是很大，想想办法把它清掉算了
iRedMail官方论坛上面已经有人问过了:
A solution to ClamAV consuming too much memory

1. In /etc/amavis/conf.d/50-user, find the following:

@av_scanners = (
    #### http://www.clamav.net/
    ['ClamAV-clamd',
    \&ask_daemon, ["CONTSCAN {}\n", "/var/run/clamav/clamd.ctl"],
    qr/\bOK$/, qr/\bFOUND$/,
    qr/^.*?: (?!Infected Archive)(.*) FOUND$/ ],
);

@av_scanners_backup = (
    ### http://www.clamav.net/   - backs up clamd or Mail::ClamAV
    ['ClamAV-clamscan', 'clamscan',
    "--stdout --disable-summary -r --tempdir=$TEMPBASE {}", [0], [1],
    qr/^.*?: (?!Infected Archive)(.*) FOUND$/ ],
);

1. Comment out the ClamAV-clamd block, and copy the ClamAV-clamscan block from @av_scanners_backup into @av_scanners, like this:

@av_scanners = (
    #### http://www.clamav.net/
    #['ClamAV-clamd',
    #\&ask_daemon, ["CONTSCAN {}\n", "/var/run/clamav/clamd.ctl"],
    #qr/\bOK$/, qr/\bFOUND$/,
    #qr/^.*?: (?!Infected Archive)(.*) FOUND$/ ],

    ### http://www.clamav.net/   - backs up clamd or Mail::ClamAV
    ['ClamAV-clamscan', 'clamscan',
    "--stdout --disable-summary -r --tempdir=$TEMPBASE {}", [0], [1],
    qr/^.*?: (?!Infected Archive)(.*) FOUND$/ ],
);

@av_scanners_backup = (
    ### http://www.clamav.net/   - backs up clamd or Mail::ClamAV
    ['ClamAV-clamscan', 'clamscan',
    "--stdout --disable-summary -r --tempdir=$TEMPBASE {}", [0], [1],
    qr/^.*?: (?!Infected Archive)(.*) FOUND$/ ],
);

然后删掉/etc/rc2.d/K01clamav-freshclam,新建一个/etc/cron.d/clamav-freshclam,实现每4个小时扫描一次:

# /etc/cron.d/clamav-freshclam
# freshen signatures every 4 hours
23 0,4,8,12,16,20  * * *  clamav  /etc/init.d/clamav-freshclam no-daemon

再把sysctl的swap参数调一下:(来源:Understanding vm.swappiness)

vm.swappiness=1

The value of 60 is a compromise that works well for modern desktop

1. A smaller value is a recommended option for a server system,
2. As the Red Hat Performance Tuning manual points out， a
3. swappiness value is recommended for database workloads. For

example, for Oracle databases, Red Hat recommends a swappiness value
of 10. In contrast, for MariaDB databases, it is recommended to set
swappiness to a value of 1.

操作了一下现在轻松多了:

[email protected]:~# free -m
              total        used        free      shared  buff/cache   available
Mem:           1994         527         943          10         523        1308
Swap:          2047         693        1354

Patoto server now fast again!