我通过 Putty 或 VNC 连接到 RHEL 5.7 服务器（不确定这是否重要），但是当我尝试运行时screen，需要永远（大约 20-30 秒）。如果我跑步screen -ls，同样的事情，需要同样的时间。
screen不知道和哪里配置有关系吗？但是当我去的时候$HOME，没有.screenrc文件。 （那么它在哪里？我读到我可以定义自己的位置，所以也许这是一个小问题......）
screen -v给出Screen version 4.00.03 (FAU) 23-Oct-06
有谁对问题可能是什么有想法，还是就是这样？
更新2
- 我尝试设置环境变量
$SCREENDIR和$SCREENRC到~/.screenrc服务器上的某个位置/home/myusername=没有变化 - 我尝试过空白
.screenrc文件 = 没有更改 - 我尝试添加
defnonblock on=.screenrc没有改变 - 还尝试使用附加
-f选项运行 strace，但没有注意到任何新信息？
strace 文件 #2，片段 1，第一次出现那个有趣的数字4294967295
11:24:23 connect(4, {sa_family=AF_FILE, path="/dev/log"...}, 110) = 0
11:24:23 sendto(4, "<14>Jun 25 11:24:23 screen: nss_"..., 129, MSG_NOSIGNAL, NULL, 0) = 129
11:24:23 write(3, "\27\3\1\0\33\331\331\30\274MD\374s\375ia\341!\200\16\4&\205\177\320\274\213\224gz\376l", 32) = 32
11:24:23 write(3, "\25\3\1\0\26\304\345w\317\273\257\256\322\314.\20T\372;'EQ\222\10z\375\234", 27) = 27
11:24:23 shutdown(3, 2 /* send and receive */) = 0
11:24:23 close(3) = 0
11:24:23 read(4294967295, 0xe5d3350, 5) = -1 EBADF (Bad file descriptor)
11:24:23 shutdown(4294967295, 2 /* send and receive */) = -1 EBADF (Bad file descriptor)
11:24:23 close(4294967295) = -1 EBADF (Bad file descriptor)
11:24:23 stat("/etc/ldap.conf", {st_mode=S_IFREG|0644, st_size=10681, ...}) = 0
11:24:23 geteuid() = 287621
11:24:23 open("/etc/hosts", O_RDONLY) = 3
新理论：在这些调用之间nanosleep，我看到它正在使用 unix 身份验证服务器执行某些操作。它在做什么或为什么......我不知道。但随后出现了这一行
sendto(4, "<14>6 月 25 日 11:24:28 屏幕: nss_"..., 129, MSG_NOSIGNAL, NULL, 0) = 129
我无法阅读完整的错误消息？然后，出现“错误文件描述符”行，并且巴姆，又要睡觉了。了解它对 unix auth 服务器的作用是否是理解这些延迟的关键？
strace 文件 #2，片段 2，放大睡眠发生前发生的事情。将公司名称和 IP 地址更改为虚拟值。
11:24:28 recvfrom(3, "\266!\201\200\0\1\0\2\0\0\0\0\10unixauth\2cs\6company\3"..., 1024, 0, {sa_family=AF_INET, sin_port=htons(53), sin_addr=inet_addr("987.654.321.09")}, [16]) = 86
11:24:28 close(3) = 0
11:24:28 socket(PF_INET, SOCK_STREAM, IPPROTO_IP) = 3
11:24:28 fcntl(3, F_SETFD, FD_CLOEXEC) = 0
11:24:28 setsockopt(3, SOL_SOCKET, SO_KEEPALIVE, [1], 4) = 0
11:24:28 setsockopt(3, SOL_TCP, TCP_NODELAY, [1], 4) = 0
11:24:28 fcntl(3, F_GETFL) = 0x2 (flags O_RDWR)
11:24:28 fcntl(3, F_SETFL, O_RDWR|O_NONBLOCK) = 0
11:24:28 connect(3, {sa_family=AF_INET, sin_port=htons(636), sin_addr=inet_addr("123.456.789.01")}, 16) = -1 EINPROGRESS (Operation now in progress)
11:24:28 poll([{fd=3, events=POLLOUT|POLLERR|POLLHUP}], 1, 90000) = 1 ([{fd=3, revents=POLLOUT}])
11:24:28 getpeername(3, {sa_family=AF_INET, sin_port=htons(636), sin_addr=inet_addr("123.456.789.01")}, [4294967312]) = 0
11:24:28 fcntl(3, F_GETFL) = 0x802 (flags O_RDWR|O_NONBLOCK)
11:24:28 fcntl(3, F_SETFL, O_RDWR) = 0
11:24:28 write(3, "\200w\1\3\1\0N\0\0\0 \0\0009\0\0008\0\0005\0\0\26\0\0\23\0\0\n\7\0\300"..., 121) = 121
11:24:28 read(3, "\26\3\1\0Q\2\0", 7) = 7
11:24:28 read(3, "\0M\3\1^\270\3\2\277\353\23\377\211\336\255Q\213\342\272\236@\242\252\5\357T\254\207\326\377Jl"..., 79) = 79
11:24:28 read(3, "\26\3\1\16\356", 5) = 5
11:24:28 read(3, "\v\0\16\352\0\16\347\0\4\2520\202\4\2460\202\3\216\240\3\2\1\2\2\3\v\334/0\r\6\t"..., 3822) = 3822
11:24:28 read(3, "\26\3\1\0\4", 5) = 5
11:24:28 read(3, "\16\0\0\0", 4) = 4
11:24:28 write(3, "\26\3\1\0\206\20\0\0\202\0\200+\34JE5\2234\204I\233g@&m\4\232\317\335\323\373\366"..., 186) = 186
11:24:28 read(3, "\24\3\1\0\1", 5) = 5
11:24:28 read(3, "\1", 1) = 1
11:24:28 read(3, "\26\3\1\0$", 5) = 5
11:24:28 read(3, "j\213\362\240R\244\35\257\243/\311\307\360\206\362\314\3\227\353\351\243\242=\222k\0y\367\20\\[\245"..., 36) = 36
11:24:28 write(3, "\27\3\1\0\214\216\374\314\342\264p\205j?\311\356#d\200\25]1\256\371\341\215\325\275jj\26\273"..., 145) = 145
11:24:28 poll([{fd=3, events=POLLIN|POLLPRI|POLLERR|POLLHUP}], 1, 90000) = 1 ([{fd=3, revents=POLLIN}])
11:24:28 read(3, "\27\3\1\0\255", 5) = 5
11:24:28 read(3, "s\315\357J\363\342\37\10\r\251\333v\302\357\207\3429\3633\345\5\17j\35*K\216\300\225,\r\265"..., 173) = 173
11:24:28 sendto(4, "<14>Jun 25 11:24:28 screen: nss_"..., 129, MSG_NOSIGNAL, NULL, 0) = 129
11:24:28 write(3, "\27\3\1\0\33H\6eq\267(\356\35\366i\364H\372m\17O\7\307d;&\37\345f\212\320H", 32) = 32
11:24:28 write(3, "\25\3\1\0\26\245\267\236\270a\356\227\233\243e\0[3\372\226\33\342f\306\257[ ", 27) = 27
11:24:28 shutdown(3, 2 /* send and receive */) = 0
11:24:28 close(3) = 0
11:24:28 read(4294967295, 0xe5d3350, 5) = -1 EBADF (Bad file descriptor)
11:24:28 shutdown(4294967295, 2 /* send and receive */) = -1 EBADF (Bad file descriptor)
11:24:28 close(4294967295) = -1 EBADF (Bad file descriptor)
11:24:28 sendto(4, "<14>Jun 25 11:24:28 screen: nss_"..., 89, MSG_NOSIGNAL, NULL, 0) = 89
11:24:28 rt_sigprocmask(SIG_BLOCK, [CHLD], [], 8) = 0
11:24:28 rt_sigaction(SIGCHLD, NULL, {SIG_DFL, [], 0}, 8) = 0
11:24:28 rt_sigprocmask(SIG_SETMASK, [], NULL, 8) = 0
11:24:28 nanosleep({8, 0}, {8, 0}) = 0
更新1
这是 strace 有趣的部分...我看到它在nanosleep重复执行（每次将睡眠时间加倍），但为什么呢？
09:10:05 read(4294967295, 0xca3b350, 5) = -1 EBADF (Bad file descriptor)
09:10:05 shutdown(4294967295, 2 /* send and receive */) = -1 EBADF (Bad file descriptor)
09:10:05 close(4294967295) = -1 EBADF (Bad file descriptor)
09:10:05 sendto(4, "<14>Jun 25 09:10:05 screen: nss_"..., 89, MSG_NOSIGNAL, NULL, 0) = 89
09:10:05 rt_sigprocmask(SIG_BLOCK, [CHLD], [], 8) = 0
09:10:05 rt_sigaction(SIGCHLD, NULL, {SIG_DFL, [], 0}, 8) = 0
09:10:05 rt_sigprocmask(SIG_SETMASK, [], NULL, 8) = 0
09:10:05 nanosleep({4, 0}, {4, 0}) = 0
09:10:12 stat("/etc/ldap.conf", {st_mode=S_IFREG|0644, st_size=10681, ...}) = 0
09:10:12 geteuid() = 287621
09:10:12 open("/etc/hosts", O_RDONLY) = 3
09:10:12 fcntl(3, F_GETFD) = 0
...
09:10:20 read(4294967295, 0xca3b350, 5) = -1 EBADF (Bad file descriptor)
09:10:20 shutdown(4294967295, 2 /* send and receive */) = -1 EBADF (Bad file descriptor)
09:10:20 close(4294967295) = -1 EBADF (Bad file descriptor)
09:10:20 sendto(4, "<14>Jun 25 09:10:20 screen: nss_"..., 90, MSG_NOSIGNAL, NULL, 0) = 90
09:10:20 rt_sigprocmask(SIG_BLOCK, [CHLD], [], 8) = 0
09:10:20 rt_sigaction(SIGCHLD, NULL, {SIG_DFL, [], 0}, 8) = 0
09:10:20 rt_sigprocmask(SIG_SETMASK, [], NULL, 8) = 0
09:10:20 nanosleep({16, 0}, {16, 0}) = 0
09:10:36 stat("/etc/ldap.conf", {st_mode=S_IFREG|0644, st_size=10681, ...}) = 0
09:10:36 geteuid() = 287621
09:10:36 open("/etc/hosts", O_RDONLY) = 3
09:10:36 fcntl(3, F_GETFD) = 0
...
09:10:36 write(3, "\27\3\1\0\33P\314s\21L-y\316\324\0\345!hd\212\351Q\33\345\335K\3\22\260r\312\332", 32) = 32
09:10:36 write(3, "\25\3\1\0\26V\20\224{t2\364\250k\241\363\363\337V\370\236m\261I\240xw", 27) = 27
09:10:36 shutdown(3, 2 /* send and receive */) = 0
09:10:36 close(3) = 0
09:10:36 read(4294967295, 0xca3b350, 5) = -1 EBADF (Bad file descriptor)
09:10:36 shutdown(4294967295, 2 /* send and receive */) = -1 EBADF (Bad file descriptor)
09:10:36 close(4294967295) = -1 EBADF (Bad file descriptor)
09:10:36 sendto(4, "<14>Jun 25 09:10:36 screen: nss_"..., 90, MSG_NOSIGNAL, NULL, 0) = 90
09:10:36 rt_sigprocmask(SIG_BLOCK, [CHLD], [], 8) = 0
09:10:36 rt_sigaction(SIGCHLD, NULL, {SIG_DFL, [], 0}, 8) = 0
09:10:36 rt_sigprocmask(SIG_SETMASK, [], NULL, 8) = 0
09:10:36 nanosleep({32, 0}, {32, 0}) = 0
09:11:08 stat("/etc/ldap.conf", {st_mode=S_IFREG|0644, st_size=10681, ...}) = 0
09:11:08 geteuid() = 287621
09:11:08 open("/etc/hosts", O_RDONLY) = 3
09:11:08 fcntl(3, F_GETFD) = 0
09:11:08 fcntl(3, F_SETFD, FD_CLOEXEC) = 0
...
09:11:08 rt_sigprocmask(SIG_BLOCK, [CHLD], [], 8) = 0
09:11:08 rt_sigaction(SIGCHLD, NULL, {SIG_DFL, [], 0}, 8) = 0
09:11:08 rt_sigprocmask(SIG_SETMASK, [], NULL, 8) = 0
09:11:08 nanosleep({64, 0}, {64, 0}) = 0
09:12:12 stat("/etc/ldap.conf", {st_mode=S_IFREG|0644, st_size=10681, ...}) = 0
09:12:12 geteuid() = 287621
09:12:12 open("/etc/hosts", O_RDONLY) = 3
09:12:12 fcntl(3, F_GETFD) = 0
答案1
当我们遇到这种情况时，我们的常驻运维天才将其范围缩小到速度较慢的 LDAP 服务器。短期修复是从/etc/ldap.conf文件中删除有问题的 LDAP 服务器。