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BIND 名称服务器的数据包队列性能差异

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BIND 名称服务器的数据包队列性能差异

背景：

我继承了一个高容量缓存名称服务器环境（Redhat Enterprise Linux 5.8，IBM System x3550），该环境的环形缓冲区设置不一致：eth0 为 1020，eth1 为 255。eth0 连接到其本地数据中心的交换机 1，eth1 连接到其本地数据中心的交换机 2。集群中的每个服务器都会在 eth0 或 eth1 之间交替作为活动接口，并且每个集群都位于不同的区域。环形缓冲区显然需要保持一致。

事情变得更加棘手：我在研究为什么许多名称服务器频繁记录“发送响应错误：未设置”错误时发现了上述问题，这ISC 知识库建议与出站拥堵有关. 具有较高环形缓冲区设置 (1020) 的服务器在 ifconfig 上丢弃的数据包较少（正如人们所预料的那样），但往往会以很高的频率记录上述错误，在我的最高负载组之一中，每天约 20k 次。我们将其称为“第 1 组”。具有较低环形缓冲区设置 (255) 的服务器每天丢弃的入站数据包明显较多（同样，这是预料之中的），但 BIND 错误实例要少得多，在同一负载组中通常为 0-150。

这里也没有什么大秘密。缓存 DNS 是一种递归服务：如果某些内容未缓存，服务器必须针对该问题进行多次查询，直到最终返回答案。这是一种 (一进)->(多出) 查询关系。修复 RX 环形缓冲区应该会导致该数字全面均衡为一个新值，从那里开始，调整内核在 proc 中的出站网络队列 (wmem_max/wmem_default) 可能是一个好主意。

我喜欢能够衡量配置更改对性能问题的影响，因此在开始进行生产更改之前，我写了一份报告来收集一些数据。以下是第 1 组中前两台服务器的输出示例：

group1-01
    RX: 7166.27/sec av.
    TX: 7432.57/sec av.
    RXDROP: 7.43/sec av.
    unset_err: 27633
group1-02
    RX: 7137.37/sec av.
    TX: 7398.50/sec av.
    RXDROP: 9.94/sec av.
    unset_err: 107

这些是公式。请注意，这是一个本地脚本，不依赖于必须在每个服务器上维护的 shell 脚本。

    RXPACK=$(ssh $server "sar -n DEV -f /var/log/sa/sa$(date --date=yesterday '+%d') | grep \"Average: .*\$(awk '{if (\$2 == "00000000") { print \$1 }}' /proc/net/route)\" | awk '{print \$3}'" 2>/dev/null)
    TXPACK=$(ssh $server "sar -n DEV -f /var/log/sa/sa$(date --date=yesterday '+%d') | grep \"Average: .*\$(awk '{if (\$2 == "00000000") { print \$1 }}' /proc/net/route)\" | awk '{print \$4}'" 2>/dev/null)
    RXDROP=$(ssh $server "sar -n EDEV -f /var/log/sa/sa$(date --date=yesterday '+%d') | grep \"Average: .*\$(awk '{if (\$2 == "00000000") { print \$1 }}' /proc/net/route)\" | awk '{print \$6}'" 2>/dev/null)
    TXDROP=$(ssh $server "sudo grep 'error sending response: unset' /var/log/dns_named.1" 2>/dev/null | wc -l)

当我开始在所有缓存 DNS 环境中运行此报告时，我注意到另一个具有几乎相同数据包负载的组（我们将其称为第 2 组），没有任何问题：

group2-01
    RX: 7066.44/sec av.
    TX: 7345.95/sec av.
    RXDROP: 0.00/sec av.
    unset_err: 0
group2-02
    RX: 7019.18/sec av.
    TX: 7312.47/sec av.
    RXDROP: 0.00/sec av.
    unset_err: 0

问题：

为什么 group2 会这样表现，而不需要进一步调整 RX 环形缓冲区或net.core.wmem_default/ net.core.wmem_max？不管怎样，我都需要对环形缓冲区进行规范化，但在开始使用 /proc 中的 wmem 值之前，我想了解这里还发生了什么。

我唯一能想到的是应用程序清空队列的速度更快，但网络堆栈调整不是我有丰富实践经验的东西，我想听听第二意见。（我不会否认，看到一些 ethtool 计数器名称我就眼花缭乱）

我已经排除了以下可能性。证明在分隔符后面。

  • 环形缓冲区布局相同。（组 1 和组 2 的第一个服务器配置相同，组 1 和组 2 的第二个服务器配置相同）
  • 默认网关布局相同。
  • 网卡是一样的。（Broadcom BCM5708）
  • ethtool 报告的固件版本相同。（bc 4.0.3 ipms 1.6.0）
  • sysctl -a输出两个组的第一个服务器与两个组的第二个服务器之间的匹配项。（不包括内核和 fs 部分）
  • 第 1 组和第 2 组的服务器总数相同。（10）

出于保密原因，我无法显示原始的named.conf，也无法显示我用来排除信息的grep过滤器。您必须相信我的话，以下配置参数在所有四台服务器之间都是恒定的：

    notify no;
    allow-transfer { none; };
    allow-recursion { any; };
    allow-query { any; };
    allow-query-cache { any; };
    recursive-clients 100000;
    max-cache-size 2G;
    max-ncache-ttl 900;

下面是大量的系统信息。“hosthash”只是为了证明循环的每次迭代实际上都在访问不同的服务器，而不会透露实际的主机名。

主机哈希：

group1-1: dc78abcb154b74c87feecb3f35222263d40c028c
group1-2: 9fe491d58fd1e7d4e21e5bf10c164e4cf66e884b
group2-1: fc76bb3ee1ff580c6aba0d685713bb4145bd5fe3
group2-2: b7550c65d37622a131b1e47f066773defbb4d817

for server in $group1_1 $group1_2 $group2_1 $group2_2
do
    echo ____________________
    ssh $server "echo -en hosthash: \$(echo \$HOSTNAME | sha1sum)\\\n\\\n &&
         SARFILE=/var/log/sa/sa\$(date --date=yesterday '+%d') &&
         uname -srvmpio &&
         sudo /usr/sbin/dmidecode -s system-product-name
         dmesg | grep Broadcom &&
         head /proc/cpuinfo &&
         GWIF=\$(awk '{if (\$2 == 00000000) { print \$1 }}' /proc/net/route) &&
         sar -n DEV -f \$SARFILE | egrep '(IFACE|Average)' &&
         sar -n EDEV -f \$SARFILE | egrep '(IFACE|Average)' &&
         sudo /sbin/ethtool \$GWIF &&
         sudo /sbin/ethtool -i \$GWIF &&
         sudo /sbin/ethtool -g \$GWIF &&
         sudo /sbin/ethtool -c \$GWIF &&
         sudo /sbin/ethtool -S \$GWIF &&
         echo sysctl linecount: \$(sudo /sbin/sysctl -a | egrep -v '^(fs|kernel)' | wc -l) &&
         echo sysctl hash: \$(sudo /sbin/sysctl -a | egrep -v '^(fs|kernel)' | sha1sum)"
done

输出：

____________________
hosthash: dc78abcb154b74c87feecb3f35222263d40c028c -

Linux 2.6.18-308.16.1.el5 #1 SMP Tue Sep 18 07:21:07 EDT 2012 x86_64 x86_64 x86_64 GNU/Linux
IBM System x3550 -[7978AC1]-
bnx2: Broadcom NetXtreme II Gigabit Ethernet Driver bnx2 v2.1.11 (July 20, 2011)
eth0: Broadcom NetXtreme II BCM5708 1000Base-T (B2) PCI-X 64-bit 133MHz found at mem c8000000, IRQ 90, node addr 001a649db00e
eth1: Broadcom NetXtreme II BCM5708 1000Base-T (B2) PCI-X 64-bit 133MHz found at mem ce000000, IRQ 177, node addr 001a649db010
cnic: Broadcom NetXtreme II CNIC Driver cnic v2.5.7 (July 20, 2011)
Broadcom NetXtreme II iSCSI Driver bnx2i v2.7.0.3 (Aug 04, 2011)
processor   : 0
vendor_id   : GenuineIntel
cpu family  : 6
model       : 23
model name  : Intel(R) Xeon(R) CPU           E5420  @ 2.50GHz
stepping    : 6
cpu MHz     : 2493.750
cache size  : 6144 KB
physical id : 0
siblings    : 4
12:00:01 AM     IFACE   rxpck/s   txpck/s   rxbyt/s   txbyt/s   rxcmp/s   txcmp/s  rxmcst/s
Average:           lo   1269.15   1269.15 206600.39 206600.39      0.00      0.00      0.00
Average:         eth0   7166.27   7432.57 704051.80 2419779.42      0.00      0.00      0.94
Average:         eth1      0.00      0.00      0.00      0.00      0.00      0.00      0.00
Average:         sit0      0.00      0.00      0.00      0.00      0.00      0.00      0.00
12:00:01 AM     IFACE   rxerr/s   txerr/s    coll/s  rxdrop/s  txdrop/s  txcarr/s  rxfram/s  rxfifo/s  txfifo/s
Average:           lo      0.00      0.00      0.00      0.00      0.00      0.00      0.00      0.00      0.00
Average:         eth0      0.00      0.00      0.00      7.43      0.00      0.00      0.00      0.00      0.00
Average:         eth1      0.00      0.00      0.00      0.00      0.00      0.00      0.00      0.00      0.00
Average:         sit0      0.00      0.00      0.00      0.00      0.00      0.00      0.00      0.00      0.00
driver: bnx2
version: 2.1.11
firmware-version: bc 4.0.3 ipms 1.6.0
bus-info: 0000:04:00.0
Ring parameters for eth0:
Pre-set maximums:
RX:     2040
RX Mini:    0
RX Jumbo:   8160
TX:     255
Current hardware settings:
RX:     1020
RX Mini:    0
RX Jumbo:   0
TX:     255

Coalesce parameters for eth0:
Adaptive RX: off  TX: off
stats-block-usecs: 999936
sample-interval: 0
pkt-rate-low: 0
pkt-rate-high: 0

rx-usecs: 18
rx-frames: 12
rx-usecs-irq: 18
rx-frames-irq: 2

tx-usecs: 80
tx-frames: 20
tx-usecs-irq: 18
tx-frames-irq: 2

rx-usecs-low: 0
rx-frame-low: 0
tx-usecs-low: 0
tx-frame-low: 0

rx-usecs-high: 0
rx-frame-high: 0
tx-usecs-high: 0
tx-frame-high: 0

NIC statistics:
     rx_bytes: 1505439501410
     rx_error_bytes: 0
     tx_bytes: 4672574845104
     tx_error_bytes: 0
     rx_ucast_packets: 15315548049
     rx_mcast_packets: 2035415
     rx_bcast_packets: 1101989
     tx_ucast_packets: 15505474251
     tx_mcast_packets: 40018
     tx_bcast_packets: 36019
     tx_mac_errors: 0
     tx_carrier_errors: 0
     rx_crc_errors: 0
     rx_align_errors: 0
     tx_single_collisions: 0
     tx_multi_collisions: 0
     tx_deferred: 0
     tx_excess_collisions: 0
     tx_late_collisions: 0
     tx_total_collisions: 0
     rx_fragments: 0
     rx_jabbers: 0
     rx_undersize_packets: 0
     rx_oversize_packets: 0
     rx_64_byte_packets: 92309552
     rx_65_to_127_byte_packets: 1243637891
     rx_128_to_255_byte_packets: 790117566
     rx_256_to_511_byte_packets: 127197337
     rx_512_to_1023_byte_packets: 168929387
     rx_1024_to_1522_byte_packets: 11591832
     rx_1523_to_9022_byte_packets: 0
     tx_64_byte_packets: 60586118
     tx_65_to_127_byte_packets: 1976738758
     tx_128_to_255_byte_packets: 2830395753
     tx_256_to_511_byte_packets: 157607989
     tx_512_to_1023_byte_packets: 1483716940
     tx_1024_to_1522_byte_packets: 406821340
     tx_1523_to_9022_byte_packets: 0
     rx_xon_frames: 0
     rx_xoff_frames: 0
     tx_xon_frames: 116422
     tx_xoff_frames: 134780
     rx_mac_ctrl_frames: 0
     rx_filtered_packets: 0
     rx_ftq_discards: 0
     rx_discards: 0
     rx_fw_discards: 14015105
sysctl linecount: 504
sysctl hash: dd6aab90d0fd9ae90742c5f812a78734e2f2ff1c -
____________________
hosthash: 9fe491d58fd1e7d4e21e5bf10c164e4cf66e884b -

Linux 2.6.18-308.16.1.el5 #1 SMP Tue Sep 18 07:21:07 EDT 2012 x86_64 x86_64 x86_64 GNU/Linux
IBM System x3550 -[7978EHU]-
bnx2: Broadcom NetXtreme II Gigabit Ethernet Driver bnx2 v2.1.11 (July 20, 2011)
eth0: Broadcom NetXtreme II BCM5708 1000Base-T (B2) PCI-X 64-bit 133MHz found at mem c8000000, IRQ 90, node addr 001a6479655c
eth1: Broadcom NetXtreme II BCM5708 1000Base-T (B2) PCI-X 64-bit 133MHz found at mem ce000000, IRQ 177, node addr 001a6479655e
cnic: Broadcom NetXtreme II CNIC Driver cnic v2.5.7 (July 20, 2011)
Broadcom NetXtreme II iSCSI Driver bnx2i v2.7.0.3 (Aug 04, 2011)
processor   : 0
vendor_id   : GenuineIntel
cpu family  : 6
model       : 23
model name  : Intel(R) Xeon(R) CPU           E5420  @ 2.50GHz
stepping    : 6
cpu MHz     : 2493.746
cache size  : 6144 KB
physical id : 0
siblings    : 4
12:00:01 AM     IFACE   rxpck/s   txpck/s   rxbyt/s   txbyt/s   rxcmp/s   txcmp/s  rxmcst/s
Average:           lo   1261.04   1261.04 205548.08 205548.08      0.00      0.00      0.00
Average:         eth0      0.00      0.00      0.00      0.00      0.00      0.00      0.00
Average:         eth1   7137.37   7398.50 702340.35 2409580.71      0.00      0.00      0.97
Average:         sit0      0.00      0.00      0.00      0.00      0.00      0.00      0.00
12:00:01 AM     IFACE   rxerr/s   txerr/s    coll/s  rxdrop/s  txdrop/s  txcarr/s  rxfram/s  rxfifo/s  txfifo/s
Average:           lo      0.00      0.00      0.00      0.00      0.00      0.00      0.00      0.00      0.00
Average:         eth0      0.00      0.00      0.00      0.00      0.00      0.00      0.00      0.00      0.00
Average:         eth1      0.00      0.00      0.00      9.94      0.00      0.00      0.00      0.00      0.00
Average:         sit0      0.00      0.00      0.00      0.00      0.00      0.00      0.00      0.00      0.00
driver: bnx2
version: 2.1.11
firmware-version: bc 4.0.3 ipms 1.6.0
bus-info: 0000:06:00.0
Ring parameters for eth1:
Pre-set maximums:
RX:     2040
RX Mini:    0
RX Jumbo:   8160
TX:     255
Current hardware settings:
RX:     255
RX Mini:    0
RX Jumbo:   0
TX:     255

Coalesce parameters for eth1:
Adaptive RX: off  TX: off
stats-block-usecs: 999936
sample-interval: 0
pkt-rate-low: 0
pkt-rate-high: 0

rx-usecs: 18
rx-frames: 12
rx-usecs-irq: 18
rx-frames-irq: 2

tx-usecs: 80
tx-frames: 20
tx-usecs-irq: 18
tx-frames-irq: 2

rx-usecs-low: 0
rx-frame-low: 0
tx-usecs-low: 0
tx-frame-low: 0

rx-usecs-high: 0
rx-frame-high: 0
tx-usecs-high: 0
tx-frame-high: 0

NIC statistics:
     rx_bytes: 1501719289640
     rx_error_bytes: 0
     tx_bytes: 4654179094291
     tx_error_bytes: 0
     rx_ucast_packets: 15253610508
     rx_mcast_packets: 2108112
     rx_bcast_packets: 1136240
     tx_ucast_packets: 15438361249
     tx_mcast_packets: 40135
     tx_bcast_packets: 1721
     tx_mac_errors: 0
     tx_carrier_errors: 0
     rx_crc_errors: 0
     rx_align_errors: 0
     tx_single_collisions: 0
     tx_multi_collisions: 0
     tx_deferred: 0
     tx_excess_collisions: 0
     tx_late_collisions: 0
     tx_total_collisions: 0
     rx_fragments: 0
     rx_jabbers: 0
     rx_undersize_packets: 0
     rx_oversize_packets: 0
     rx_64_byte_packets: 92376678
     rx_65_to_127_byte_packets: 1183040190
     rx_128_to_255_byte_packets: 788176623
     rx_256_to_511_byte_packets: 126838328
     rx_512_to_1023_byte_packets: 168170816
     rx_1024_to_1522_byte_packets: 13350337
     rx_1523_to_9022_byte_packets: 0
     tx_64_byte_packets: 60806588
     tx_65_to_127_byte_packets: 1955234150
     tx_128_to_255_byte_packets: 2806601346
     tx_256_to_511_byte_packets: 154015585
     tx_512_to_1023_byte_packets: 1466206531
     tx_1024_to_1522_byte_packets: 405928513
     tx_1523_to_9022_byte_packets: 0
     rx_xon_frames: 0
     rx_xoff_frames: 0
     tx_xon_frames: 150648
     tx_xoff_frames: 173552
     rx_mac_ctrl_frames: 0
     rx_filtered_packets: 1
     rx_ftq_discards: 0
     rx_discards: 0
     rx_fw_discards: 19605427
sysctl linecount: 504
sysctl hash: 4626e3788c72e091487afe1e3a7cfd32278ab07d -
____________________
hosthash: fc76bb3ee1ff580c6aba0d685713bb4145bd5fe3 -

Linux 2.6.18-308.16.1.el5 #1 SMP Tue Sep 18 07:21:07 EDT 2012 x86_64 x86_64 x86_64 GNU/Linux
IBM System x3550 -[7978AC1]-
bnx2: Broadcom NetXtreme II Gigabit Ethernet Driver bnx2 v2.1.11 (July 20, 2011)
eth0: Broadcom NetXtreme II BCM5708 1000Base-T (B2) PCI-X 64-bit 133MHz found at mem c8000000, IRQ 90, node addr 001a649dc68a
eth1: Broadcom NetXtreme II BCM5708 1000Base-T (B2) PCI-X 64-bit 133MHz found at mem ce000000, IRQ 177, node addr 001a649dc68c
cnic: Broadcom NetXtreme II CNIC Driver cnic v2.5.7 (July 20, 2011)
Broadcom NetXtreme II iSCSI Driver bnx2i v2.7.0.3 (Aug 04, 2011)
processor   : 0
vendor_id   : GenuineIntel
cpu family  : 6
model       : 23
model name  : Intel(R) Xeon(R) CPU           E5420  @ 2.50GHz
stepping    : 6
cpu MHz     : 2493.750
cache size  : 6144 KB
physical id : 0
siblings    : 4
12:00:01 AM     IFACE   rxpck/s   txpck/s   rxbyt/s   txbyt/s   rxcmp/s   txcmp/s  rxmcst/s
Average:           lo   1891.67   1891.67 266593.77 266593.77      0.00      0.00      0.00
Average:         eth0   7066.44   7345.95 730519.41 2215508.99      0.00      0.00      4.37
Average:         eth1      0.00      0.00      0.00      0.00      0.00      0.00      0.00
Average:         sit0      0.00      0.00      0.00      0.00      0.00      0.00      0.00
12:00:01 AM     IFACE   rxerr/s   txerr/s    coll/s  rxdrop/s  txdrop/s  txcarr/s  rxfram/s  rxfifo/s  txfifo/s
Average:           lo      0.00      0.00      0.00      0.00      0.00      0.00      0.00      0.00      0.00
Average:         eth0      0.00      0.00      0.00      0.00      0.00      0.00      0.00      0.00      0.00
Average:         eth1      0.00      0.00      0.00      0.00      0.00      0.00      0.00      0.00      0.00
Average:         sit0      0.00      0.00      0.00      0.00      0.00      0.00      0.00      0.00      0.00
driver: bnx2
version: 2.1.11
firmware-version: bc 4.0.3 ipms 1.6.0
bus-info: 0000:04:00.0
Ring parameters for eth0:
Pre-set maximums:
RX:     2040
RX Mini:    0
RX Jumbo:   8160
TX:     255
Current hardware settings:
RX:     1020
RX Mini:    0
RX Jumbo:   0
TX:     255

Coalesce parameters for eth0:
Adaptive RX: off  TX: off
stats-block-usecs: 999936
sample-interval: 0
pkt-rate-low: 0
pkt-rate-high: 0

rx-usecs: 18
rx-frames: 12
rx-usecs-irq: 18
rx-frames-irq: 2

tx-usecs: 80
tx-frames: 20
tx-usecs-irq: 18
tx-frames-irq: 2

rx-usecs-low: 0
rx-frame-low: 0
tx-usecs-low: 0
tx-frame-low: 0

rx-usecs-high: 0
rx-frame-high: 0
tx-usecs-high: 0
tx-frame-high: 0

NIC statistics:
     rx_bytes: 4640887074833
     rx_error_bytes: 0
     tx_bytes: 12640942400790
     tx_error_bytes: 0
     rx_ucast_packets: 46405845860
     rx_mcast_packets: 14487857
     rx_bcast_packets: 3476467
     tx_ucast_packets: 47159091638
     tx_mcast_packets: 118147
     tx_bcast_packets: 5504
     tx_mac_errors: 0
     tx_carrier_errors: 0
     rx_crc_errors: 0
     rx_align_errors: 0
     tx_single_collisions: 0
     tx_multi_collisions: 0
     tx_deferred: 0
     tx_excess_collisions: 0
     tx_late_collisions: 0
     tx_total_collisions: 0
     rx_fragments: 0
     rx_jabbers: 0
     rx_undersize_packets: 0
     rx_oversize_packets: 0
     rx_64_byte_packets: 136463411
     rx_65_to_127_byte_packets: 4245502343
     rx_128_to_255_byte_packets: 2357984838
     rx_256_to_511_byte_packets: 355610202
     rx_512_to_1023_byte_packets: 608223572
     rx_1024_to_1522_byte_packets: 65320154
     rx_1523_to_9022_byte_packets: 0
     tx_64_byte_packets: 112166114
     tx_65_to_127_byte_packets: 3010346100
     tx_128_to_255_byte_packets: 4087240164
     tx_256_to_511_byte_packets: 1625596725
     tx_512_to_1023_byte_packets: 3037109096
     tx_1024_to_1522_byte_packets: 927187571
     tx_1523_to_9022_byte_packets: 0
     rx_xon_frames: 0
     rx_xoff_frames: 0
     tx_xon_frames: 79164
     tx_xoff_frames: 89685
     rx_mac_ctrl_frames: 0
     rx_filtered_packets: 1
     rx_ftq_discards: 0
     rx_discards: 0
     rx_fw_discards: 6857729
sysctl linecount: 504
sysctl hash: dd6aab90d0fd9ae90742c5f812a78734e2f2ff1c -
____________________
hosthash: b7550c65d37622a131b1e47f066773defbb4d817 -

Linux 2.6.18-308.16.1.el5 #1 SMP Tue Sep 18 07:21:07 EDT 2012 x86_64 x86_64 x86_64 GNU/Linux
IBM System x3550 -[7978EHU]-
bnx2: Broadcom NetXtreme II Gigabit Ethernet Driver bnx2 v2.1.11 (July 20, 2011)
eth0: Broadcom NetXtreme II BCM5708 1000Base-T (B2) PCI-X 64-bit 133MHz found at mem c8000000, IRQ 90, node addr 00215e3f1ec4
eth1: Broadcom NetXtreme II BCM5708 1000Base-T (B2) PCI-X 64-bit 133MHz found at mem ce000000, IRQ 177, node addr 00215e3f1ec6
processor   : 0
vendor_id   : GenuineIntel
cpu family  : 6
model       : 23
model name  : Intel(R) Xeon(R) CPU           E5420  @ 2.50GHz
stepping    : 6
cpu MHz     : 2493.753
cache size  : 6144 KB
physical id : 1
siblings    : 4
12:00:01 AM     IFACE   rxpck/s   txpck/s   rxbyt/s   txbyt/s   rxcmp/s   txcmp/s  rxmcst/s
Average:           lo   1883.04   1883.04 263726.79 263726.79      0.00      0.00      0.00
Average:         eth0      0.00      0.00      0.00      0.00      0.00      0.00      0.00
Average:         eth1   7019.18   7312.47 720911.92 2214861.10      0.00      0.00      1.02
Average:         sit0      0.00      0.00      0.00      0.00      0.00      0.00      0.00
12:00:01 AM     IFACE   rxerr/s   txerr/s    coll/s  rxdrop/s  txdrop/s  txcarr/s  rxfram/s  rxfifo/s  txfifo/s
Average:           lo      0.00      0.00      0.00      0.00      0.00      0.00      0.00      0.00      0.00
Average:         eth0      0.00      0.00      0.00      0.00      0.00      0.00      0.00      0.00      0.00
Average:         eth1      0.00      0.00      0.00      0.00      0.00      0.00      0.00      0.00      0.00
Average:         sit0      0.00      0.00      0.00      0.00      0.00      0.00      0.00      0.00      0.00
driver: bnx2
version: 2.1.11
firmware-version: bc 4.0.3 ipms 1.6.0
bus-info: 0000:06:00.0
Ring parameters for eth1:
Pre-set maximums:
RX:     2040
RX Mini:    0
RX Jumbo:   8160
TX:     255
Current hardware settings:
RX:     255
RX Mini:    0
RX Jumbo:   0
TX:     255

Coalesce parameters for eth1:
Adaptive RX: off  TX: off
stats-block-usecs: 999936
sample-interval: 0
pkt-rate-low: 0
pkt-rate-high: 0

rx-usecs: 18
rx-frames: 12
rx-usecs-irq: 18
rx-frames-irq: 2

tx-usecs: 80
tx-frames: 20
tx-usecs-irq: 18
tx-frames-irq: 2

rx-usecs-low: 0
rx-frame-low: 0
tx-usecs-low: 0
tx-frame-low: 0

rx-usecs-high: 0
rx-frame-high: 0
tx-usecs-high: 0
tx-frame-high: 0

NIC statistics:
     rx_bytes: 4621548539323
     rx_error_bytes: 0
     tx_bytes: 12598031299743
     tx_error_bytes: 0
     rx_ucast_packets: 46260356368
     rx_mcast_packets: 5352446
     rx_bcast_packets: 3474589
     tx_ucast_packets: 47008853953
     tx_mcast_packets: 118164
     tx_bcast_packets: 5471
     tx_mac_errors: 0
     tx_carrier_errors: 0
     rx_crc_errors: 0
     rx_align_errors: 0
     tx_single_collisions: 0
     tx_multi_collisions: 0
     tx_deferred: 0
     tx_excess_collisions: 0
     tx_late_collisions: 0
     tx_total_collisions: 0
     rx_fragments: 0
     rx_jabbers: 0
     rx_undersize_packets: 0
     rx_oversize_packets: 0
     rx_64_byte_packets: 126851062
     rx_65_to_127_byte_packets: 4117708205
     rx_128_to_255_byte_packets: 2346047550
     rx_256_to_511_byte_packets: 356266112
     rx_512_to_1023_byte_packets: 604666332
     rx_1024_to_1522_byte_packets: 62938478
     rx_1523_to_9022_byte_packets: 0
     tx_64_byte_packets: 111216848
     tx_65_to_127_byte_packets: 2984505931
     tx_128_to_255_byte_packets: 4027485330
     tx_256_to_511_byte_packets: 1577669672
     tx_512_to_1023_byte_packets: 3015060448
     tx_1024_to_1522_byte_packets: 933575954
     tx_1523_to_9022_byte_packets: 0
     rx_xon_frames: 0
     rx_xoff_frames: 0
     tx_xon_frames: 129873
     tx_xoff_frames: 145090
     rx_mac_ctrl_frames: 0
     rx_filtered_packets: 1
     rx_ftq_discards: 0
     rx_discards: 0
     rx_fw_discards: 6752713
sysctl linecount: 504
sysctl hash: 4626e3788c72e091487afe1e3a7cfd32278ab07d -

答案1

想知道这个盒子是不是戴尔的？戴尔提供的 bnx2i 驱动程序和芯片组存在一个众所周知的问题。结果是在网络负载过大的情况下随机丢弃数据包。如果是这样的话，调整后的环形缓冲区可能会触发它，这似乎是合乎逻辑的。

我相信戴尔提供了他们自己的驱动程序版本作为修复。另一个修复方法是在 modprobe.conf 中执行如下操作：

选项 bnx2i disable_msi=1

无论如何，尝试一下总不会有什么坏处。而且 x2 是 kce 所说的。这是我见过的写得最好的问题之一。

答案2

即使您确定拥有服务器的负载均衡器 VIP 的完整列表，也请运行数据包捕获。仅仅因为您的机器不响应 IP 地址的 ARP 并不意味着不能向它发送虚假数据包。确保发送到您的 MAC 地址的流量与配置的 IP 地址匹配。

我很感谢大家花时间研究这个问题，但我自己在这方面缺乏尽职调查。事后看来，我需要构建一个这样的 PCAP 过滤器：

tcpdump -i eth0 -n 'ether dst aa:bb:cc:dd:ee:ff and not (dst host 1.2.3.4 or dst host 5.6.7.8 or...)'

在哪里：

aa:bb:cc:dd:ee:ff = HW addr of eth0
1.2.3.4, 5.6.7.8  = list of destination addresses that traffic is expected on

有许多负载均衡器 VIP 未分配给我（我不控制 LB），它们在 TCP 端口 53 上传递流量的方式会导致 RX 丢弃。这些旧 IP 上的流量非常低，管理员不太可能注意到网络上的流量。

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