三个 Apache2 Web 服务器运行 PHP 5.2.3 网站。我们使用 Memcache 来缓存已呈现的页面，同时也将其用作 PHP 会话的存储引擎。
在高峰流量时段，我们的三个 Web 服务器上都会出现 Apache 分段错误，并且所有 HTTPD 子进程都会出现分段错误。
我的直觉告诉我，增加的 Memcache 流量阻止了 PHP 会话的创建或清理，因此进程终止。有人可以从以下内容证实这一点吗？：
#0 _zend_mm_free_int (heap=0x7fb67a075820, p=0x7fb67a011538) at /usr/src/debug/php-5.3.3/Zend/zend_alloc.c:2018
#1 0x00007fb665d02e82 in mmc_buffer_free (request=0x7fb67a011548) at /usr/src/debug/php-pecl-memcache-3.0.4/memcache-3.0.4/memcache_pool.c:50
#2 mmc_request_free (request=0x7fb67a011548) at /usr/src/debug/php-pecl-memcache-3.0.4/memcache-3.0.4/memcache_pool.c:169
#3 0x00007fb665d031ea in mmc_pool_free (pool=0x7fb67a00e458) at /usr/src/debug/php-pecl-memcache-3.0.4/memcache-3.0.4/memcache_pool.c:917
#4 0x00007fb665d0a2f1 in ps_close_memcache (mod_data=0x7fb66d625440) at /usr/src/debug/php-pecl-memcache-3.0.4/memcache-3.0.4/memcache_session.c:185
#5 0x00007fb66d1b0935 in php_session_save_current_state () at /usr/src/debug/php-5.3.3/ext/session/session.c:625
#6 php_session_flush () at /usr/src/debug/php-5.3.3/ext/session/session.c:1517
#7 0x00007fb66d1b0c1b in zm_deactivate_session (type=<value optimized out>, module_number=<value optimized out>) at /usr/src/debug/php-5.3.3/ext/session/session.c:2171
#8 0x00007fb66d2a719c in module_registry_cleanup (module=<value optimized out>) at /usr/src/debug/php-5.3.3/Zend/zend_API.c:2150
#9 0x00007fb66d2b1994 in zend_hash_reverse_apply (ht=0x7fb66d629d60, apply_func=0x7fb66d2a7180 <module_registry_cleanup>) at /usr/src/debug/php-5.3.3/Zend/zend_hash.c:755
#10 0x00007fb66d2a5c0d in zend_deactivate_modules () at /usr/src/debug/php-5.3.3/Zend/zend.c:866
#11 0x00007fb66d2541b5 in php_request_shutdown (dummy=<value optimized out>) at /usr/src/debug/php-5.3.3/main/main.c:1607
#12 0x00007fb66d32e037 in php_apache_request_dtor (r=0x7fb67a229658) at /usr/src/debug/php-5.3.3/sapi/apache2handler/sapi_apache2.c:509
#13 php_handler (r=0x7fb67a229658) at /usr/src/debug/php-5.3.3/sapi/apache2handler/sapi_apache2.c:681
#14 0x00007fb6784166f0 in ap_run_handler (r=0x7fb67a229658) at /usr/src/debug/httpd-2.2.15/server/config.c:158
#15 0x00007fb678419f58 in ap_invoke_handler (r=0x7fb67a229658) at /usr/src/debug/httpd-2.2.15/server/config.c:372
#16 0x00007fb6784254f0 in ap_process_request (r=0x7fb67a229658) at /usr/src/debug/httpd-2.2.15/modules/http/http_request.c:282
#17 0x00007fb678422418 in ap_process_http_connection (c=0x7fb67a2193a8) at /usr/src/debug/httpd-2.2.15/modules/http/http_core.c:190
#18 0x00007fb67841e1b8 in ap_run_process_connection (c=0x7fb67a2193a8) at /usr/src/debug/httpd-2.2.15/server/connection.c:43
#19 0x00007fb678429f4b in child_main (child_num_arg=<value optimized out>) at /usr/src/debug/httpd-2.2.15/server/mpm/prefork/prefork.c:662
#20 0x00007fb67842a21a in make_child (s=0x7fb679cd7860, slot=153) at /usr/src/debug/httpd-2.2.15/server/mpm/prefork/prefork.c:758
#21 0x00007fb67842aea4 in perform_idle_server_maintenance (_pconf=<value optimized out>, plog=<value optimized out>, s=<value optimized out>) at /usr/src/debug/httpd-2.2.15/server/mpm/prefork/prefork.c:893
#22 ap_mpm_run (_pconf=<value optimized out>, plog=<value optimized out>, s=<value optimized out>) at /usr/src/debug/httpd-2.2.15/server/mpm/prefork/prefork.c:1097
#23 0x00007fb678402890 in main (argc=1, argv=0x7fff6fecacb8) at /usr/src/debug/httpd-2.2.15/server/main.c:740
PHP.INI 如下：
[PHP]
engine = On
short_open_tag = On
asp_tags = Off
precision = 14
y2k_compliance = On
output_buffering = 4096
zlib.output_compression = Off
implicit_flush = Off
unserialize_callback_func =
serialize_precision = 100
allow_call_time_pass_reference = Off
safe_mode = Off
safe_mode_gid = Off
safe_mode_include_dir =
safe_mode_exec_dir =
safe_mode_allowed_env_vars = PHP_
safe_mode_protected_env_vars = LD_LIBRARY_PATH
disable_functions =
disable_classes =
expose_php = On
max_execution_time = 30
max_input_time = 60
memory_limit = 128M
error_reporting = E_ALL & ~E_DEPRECATED
display_errors = Off
display_startup_errors = Off
log_errors = Off
log_errors_max_len = 1024
ignore_repeated_errors = Off
ignore_repeated_source = Off
report_memleaks = On
track_errors = Off
html_errors = Off
variables_order = "GPCS"
request_order = "GP"
register_globals = Off
register_long_arrays = Off
register_argc_argv = Off
auto_globals_jit = On
post_max_size = 8M
magic_quotes_gpc = Off
magic_quotes_runtime = Off
magic_quotes_sybase = Off
auto_prepend_file =
auto_append_file =
default_mimetype = "text/html"
doc_root =
user_dir =
enable_dl = Off
file_uploads = On
upload_max_filesize = 2M
allow_url_fopen = On
allow_url_include = Off
default_socket_timeout = 60
[Date]
[filter]
[iconv]
[intl]
[sqlite]
[sqlite3]
[Pcre]
[Pdo]
[Phar]
[Syslog]
define_syslog_variables = Off
[mail function]
SMTP = localhost
smtp_port = 25
sendmail_path = /usr/sbin/sendmail -t -i
mail.add_x_header = On
[SQL]
sql.safe_mode = Off
[ODBC]
odbc.allow_persistent = On
odbc.check_persistent = On
odbc.max_persistent = -1
odbc.max_links = -1
odbc.defaultlrl = 4096
odbc.defaultbinmode = 1
[MySQL]
mysql.allow_persistent = On
mysql.max_persistent = -1
mysql.max_links = -1
mysql.default_port =
mysql.default_socket =
mysql.default_host =
mysql.default_user =
mysql.default_password =
mysql.connect_timeout = 60
mysql.trace_mode = Off
[MySQLi]
mysqli.max_links = -1
mysqli.default_port = 3306
mysqli.default_socket =
mysqli.default_host =
mysqli.default_user =
mysqli.default_pw =
mysqli.reconnect = Off
[PostgresSQL]
pgsql.allow_persistent = On
pgsql.auto_reset_persistent = Off
pgsql.max_persistent = -1
pgsql.max_links = -1
pgsql.ignore_notice = 0
pgsql.log_notice = 0
[Sybase-CT]
sybct.allow_persistent = On
sybct.max_persistent = -1
sybct.max_links = -1
sybct.min_server_severity = 10
sybct.min_client_severity = 10
[bcmath]
bcmath.scale = 0
[browscap]
[Session]
session.save_handler = files
session.save_path = "/var/lib/php/session"
session.use_cookies = 1
session.use_only_cookies = 1
session.name = PHPSESSID
session.auto_start = 1
session.cookie_lifetime = 0
session.cookie_path = /
session.cookie_domain =
session.cookie_httponly =
session.serialize_handler = php
session.gc_probability = 1
session.gc_divisor = 1000
session.gc_maxlifetime = 1440
session.bug_compat_42 = Off
session.bug_compat_warn = Off
session.referer_check =
session.entropy_length = 0
session.entropy_file =
session.cache_limiter = nocache
session.cache_expire = 180
session.use_trans_sid = 0
session.hash_function = 0
session.hash_bits_per_character = 5
url_rewriter.tags = "a=href,area=href,frame=src,input=src,form=fakeentry"
[MSSQL]
mssql.allow_persistent = On
mssql.max_persistent = -1
mssql.max_links = -1
mssql.min_error_severity = 10
mssql.min_message_severity = 10
mssql.compatability_mode = Off
mssql.secure_connection = Off
[Assertion]
[COM]
[mbstring]
[gd]
[exif]
[Tidy]
tidy.clean_output = Off
[soap]
soap.wsdl_cache_enabled=1
soap.wsdl_cache_dir="/tmp"
soap.wsdl_cache_ttl=86400
/etc/php.d/memcached.ini : session.save_path="tcp://memcache1:11211?persistent=1&weight=1&timeout=3&retry_interval=15"
答案1
该核心转储实际上只告诉您“我在尝试分配内存时死机了”。它并没有告诉您为什么没有成功；为此，我们需要了解崩溃时的系统状态。我们在这种错误附近看到的常见坏消息是 php 解释器进程的数量急剧增加，通常是因为它们没有死机，这通常会导致内存不足的糟糕情况。
我发现这是由于系统配置错误（错误的 sysctl 限制、过于激进的 OOMkiller 等）造成的，我也发现这是由于 PHP 代码编写不当（等待一些永不返回的外部资源，或者陷入紧密循环并永远运行）造成的。
您能否提供错误情况发生之前和期间进程数量以及系统物理内存和交换配置的统计信息？