Postgresql FATAL: could not create semaphores: No space left on device

末蓝、 2022-06-01 01:48 185阅读 0赞

转自：[http://blog.163.com/dazuiba\_008/blog/static/363349812016314739538/][http_blog.163.com_dazuiba_008_blog_static_363349812016314739538]

**今天做恢复的时候，数据库做完恢复后，无法启动报错**

**FATAL:  could not create semaphores: No space left on device**

**DETAIL:  Failed system call was semget(xxxxxxxxxx).**

**HINT:  This error does \*not\* mean that you have run out of disk space.  It occurs when either the system limit for the maximum number of semaphore sets (SEMMNI), or the system wide maximum number of semaphores (SEMMNS), would be exceeded.  You need to raise the respective kernel parameter.  Alternatively, reduce PostgreSQL's consumption of semaphores by reducing its max\_connections parameter.**

**看提示是空间不足，其实不是空间不足，是信号量不足**

**这里是共享内存段的限制，没有报错，简单介绍一下**

**如果数据库报FATAL: could not create shared memory segment:Cannot allocate memory 错误，可以考虑修改以下相关参数**

**\#ipcs -lm**

**------ Shared Memory Limits --------**

**max number of segments = 4096**

**max seg size (kbytes) = 67108864**

**max total shared memory (kbytes) = 17179869184**

**min seg size (bytes) = 1**

** \#cat  /proc/sys/kernel/shmmax**

**68719476736**

**SHMMAX 单个共享内存段最大字节数**

**\# cat  /proc/sys/kernel/shmmni**

**4096**

**SHMMNI 共享内存段最大个数 **

**\# cat  /proc/sys/kernel/shmall**

**4294967296**

**SHMALL系统中共享内存也总数，至少为ceil(shmmax/PAGE\_SIZE)**

**获取page\_size值**

**\# getconf PAGE\_SIZE**

**4096**

**可以根据实际情况修改以上参数值，在/etc/sysctl.conf配置文件中**

**今天遇到的错误，主要解决以下参数的限制才能解决我们数据库启动的报错**

**\# ipcs -ls**

**------ Semaphore Limits --------**

**max number of arrays = 1280**

**max semaphores per array = 50100**

**max semaphores system wide = 64128000**

**max ops per semop call = 50100**

**semaphore max value = 32767**

**\# cat  /proc/sys/kernel/sem**

**SEMMSL   SEMMNS         SEMOPM  SEMMNI**

**50100   128256000       50100   2560**

**SEMMSL 每个信号量set中信号量最大个数**

**SEMMNS linux系统中信号量最大个数**

**SEMOPM semop系统调用允许的信号量最大个数设置，设置成和SEMMSL一样即可**

**SEMMNI  linux系统信号量set最大个数**

**所以SEMMNS=SEMMSL\*SEMMNI**

**所以要么增大信号量，要么减少max\_connect参数**

**这里我选择增大信号量**

**修改 vi /etc/sysctl.conf 的以下参数**

**kernel.sem = 50100 128256000 50100 2560**

**修改完成后，执行：**

**\# sysctl -p **

**使修改参数生效**

**ipcs -ls**

**------ Semaphore Limits --------**

**max number of arrays = 2560**

**max semaphores per array = 50100**

**max semaphores system wide = 128256000**

**max ops per semop call = 50100**

**semaphore max value = 32767**

**重新启动数据库并无报错**

<table style=""> 
 <thead> 
  <tr> 
   <th style="border-top:rgb(167,198,223) 1px solid; border-right:rgb(167,198,223) 1px solid; border-bottom:rgb(167,198,223) 1px solid; padding-bottom:0.5ex; padding-top:0.5ex; padding-left:0.5ex; border-left:rgb(167,198,223) 1px solid; padding-right:0.5ex"> Name</th> 
   <th style="border-top:rgb(167,198,223) 1px solid; border-right:rgb(167,198,223) 1px solid; border-bottom:rgb(167,198,223) 1px solid; padding-bottom:0.5ex; padding-top:0.5ex; padding-left:0.5ex; border-left:rgb(167,198,223) 1px solid; padding-right:0.5ex"> Description</th> 
   <th style="border-top:rgb(167,198,223) 1px solid; border-right:rgb(167,198,223) 1px solid; border-bottom:rgb(167,198,223) 1px solid; padding-bottom:0.5ex; padding-top:0.5ex; padding-left:0.5ex; border-left:rgb(167,198,223) 1px solid; padding-right:0.5ex"> Reasonable values</th> 
  </tr> 
 </thead> 
 <tbody> 
  <tr> 
   <td style="border-top:rgb(167,198,223) 1px solid; border-right:rgb(167,198,223) 1px solid; border-bottom:rgb(167,198,223) 1px solid; padding-bottom:0.5ex; padding-top:0.5ex; padding-left:0.5ex; border-left:rgb(167,198,223) 1px solid; padding-right:0.5ex; background-color:rgb(255,255,255)"> SHMMAX</td> 
   <td style="border-top:rgb(167,198,223) 1px solid; border-right:rgb(167,198,223) 1px solid; border-bottom:rgb(167,198,223) 1px solid; padding-bottom:0.5ex; padding-top:0.5ex; padding-left:0.5ex; border-left:rgb(167,198,223) 1px solid; padding-right:0.5ex; background-color:rgb(255,255,255)"> Maximum size of shared memory segment (bytes)</td> 
   <td style="border-top:rgb(167,198,223) 1px solid; border-right:rgb(167,198,223) 1px solid; border-bottom:rgb(167,198,223) 1px solid; padding-bottom:0.5ex; padding-top:0.5ex; padding-left:0.5ex; border-left:rgb(167,198,223) 1px solid; padding-right:0.5ex; background-color:rgb(255,255,255)"> at least 1kB (more if running many copies of the server)</td> 
  </tr> 
  <tr> 
   <td style="border-top:rgb(167,198,223) 1px solid; border-right:rgb(167,198,223) 1px solid; border-bottom:rgb(167,198,223) 1px solid; padding-bottom:0.5ex; padding-top:0.5ex; padding-left:0.5ex; border-left:rgb(167,198,223) 1px solid; padding-right:0.5ex; background-color:rgb(255,255,255)"> SHMMIN</td> 
   <td style="border-top:rgb(167,198,223) 1px solid; border-right:rgb(167,198,223) 1px solid; border-bottom:rgb(167,198,223) 1px solid; padding-bottom:0.5ex; padding-top:0.5ex; padding-left:0.5ex; border-left:rgb(167,198,223) 1px solid; padding-right:0.5ex; background-color:rgb(255,255,255)"> Minimum size of shared memory segment (bytes)</td> 
   <td style="border-top:rgb(167,198,223) 1px solid; border-right:rgb(167,198,223) 1px solid; border-bottom:rgb(167,198,223) 1px solid; padding-bottom:0.5ex; padding-top:0.5ex; padding-left:0.5ex; border-left:rgb(167,198,223) 1px solid; padding-right:0.5ex; background-color:rgb(255,255,255)"> 1</td> 
  </tr> 
  <tr> 
   <td style="border-top:rgb(167,198,223) 1px solid; border-right:rgb(167,198,223) 1px solid; border-bottom:rgb(167,198,223) 1px solid; padding-bottom:0.5ex; padding-top:0.5ex; padding-left:0.5ex; border-left:rgb(167,198,223) 1px solid; padding-right:0.5ex; background-color:rgb(255,255,255)"> SHMALL</td> 
   <td style="border-top:rgb(167,198,223) 1px solid; border-right:rgb(167,198,223) 1px solid; border-bottom:rgb(167,198,223) 1px solid; padding-bottom:0.5ex; padding-top:0.5ex; padding-left:0.5ex; border-left:rgb(167,198,223) 1px solid; padding-right:0.5ex; background-color:rgb(255,255,255)"> Total amount of shared memory available (bytes or pages)</td> 
   <td style="border-top:rgb(167,198,223) 1px solid; border-right:rgb(167,198,223) 1px solid; border-bottom:rgb(167,198,223) 1px solid; padding-bottom:0.5ex; padding-top:0.5ex; padding-left:0.5ex; border-left:rgb(167,198,223) 1px solid; padding-right:0.5ex; background-color:rgb(255,255,255)"> if bytes, same as&nbsp;SHMMAX; if pages,&nbsp;ceil(SHMMAX/PAGE_SIZE)</td> 
  </tr> 
  <tr> 
   <td style="border-top:rgb(167,198,223) 1px solid; border-right:rgb(167,198,223) 1px solid; border-bottom:rgb(167,198,223) 1px solid; padding-bottom:0.5ex; padding-top:0.5ex; padding-left:0.5ex; border-left:rgb(167,198,223) 1px solid; padding-right:0.5ex; background-color:rgb(255,255,255)"> SHMSEG</td> 
   <td style="border-top:rgb(167,198,223) 1px solid; border-right:rgb(167,198,223) 1px solid; border-bottom:rgb(167,198,223) 1px solid; padding-bottom:0.5ex; padding-top:0.5ex; padding-left:0.5ex; border-left:rgb(167,198,223) 1px solid; padding-right:0.5ex; background-color:rgb(255,255,255)"> Maximum number of shared memory segments per process</td> 
   <td style="border-top:rgb(167,198,223) 1px solid; border-right:rgb(167,198,223) 1px solid; border-bottom:rgb(167,198,223) 1px solid; padding-bottom:0.5ex; padding-top:0.5ex; padding-left:0.5ex; border-left:rgb(167,198,223) 1px solid; padding-right:0.5ex; background-color:rgb(255,255,255)"> only 1 segment is needed, but the default is much higher</td> 
  </tr> 
  <tr> 
   <td style="border-top:rgb(167,198,223) 1px solid; border-right:rgb(167,198,223) 1px solid; border-bottom:rgb(167,198,223) 1px solid; padding-bottom:0.5ex; padding-top:0.5ex; padding-left:0.5ex; border-left:rgb(167,198,223) 1px solid; padding-right:0.5ex; background-color:rgb(255,255,255)"> SHMMNI</td> 
   <td style="border-top:rgb(167,198,223) 1px solid; border-right:rgb(167,198,223) 1px solid; border-bottom:rgb(167,198,223) 1px solid; padding-bottom:0.5ex; padding-top:0.5ex; padding-left:0.5ex; border-left:rgb(167,198,223) 1px solid; padding-right:0.5ex; background-color:rgb(255,255,255)"> Maximum number of shared memory segments system-wide</td> 
   <td style="border-top:rgb(167,198,223) 1px solid; border-right:rgb(167,198,223) 1px solid; border-bottom:rgb(167,198,223) 1px solid; padding-bottom:0.5ex; padding-top:0.5ex; padding-left:0.5ex; border-left:rgb(167,198,223) 1px solid; padding-right:0.5ex; background-color:rgb(255,255,255)"> like&nbsp;SHMSEG&nbsp;plus room for other applications</td> 
  </tr> 
  <tr> 
   <td style="border-top:rgb(167,198,223) 1px solid; border-right:rgb(167,198,223) 1px solid; border-bottom:rgb(167,198,223) 1px solid; padding-bottom:0.5ex; padding-top:0.5ex; padding-left:0.5ex; border-left:rgb(167,198,223) 1px solid; padding-right:0.5ex; background-color:rgb(255,255,255)"> SEMMNI</td> 
   <td style="border-top:rgb(167,198,223) 1px solid; border-right:rgb(167,198,223) 1px solid; border-bottom:rgb(167,198,223) 1px solid; padding-bottom:0.5ex; padding-top:0.5ex; padding-left:0.5ex; border-left:rgb(167,198,223) 1px solid; padding-right:0.5ex; background-color:rgb(255,255,255)"> Maximum number of semaphore identifiers (i.e., sets)</td> 
   <td style="border-top:rgb(167,198,223) 1px solid; border-right:rgb(167,198,223) 1px solid; border-bottom:rgb(167,198,223) 1px solid; padding-bottom:0.5ex; padding-top:0.5ex; padding-left:0.5ex; border-left:rgb(167,198,223) 1px solid; padding-right:0.5ex; background-color:rgb(255,255,255)"> at least&nbsp;ceil((max_connections + autovacuum_max_workers + max_worker_processes + 5) / 16)</td> 
  </tr> 
  <tr> 
   <td style="border-top:rgb(167,198,223) 1px solid; border-right:rgb(167,198,223) 1px solid; border-bottom:rgb(167,198,223) 1px solid; padding-bottom:0.5ex; padding-top:0.5ex; padding-left:0.5ex; border-left:rgb(167,198,223) 1px solid; padding-right:0.5ex; background-color:rgb(255,255,255)"> SEMMNS</td> 
   <td style="border-top:rgb(167,198,223) 1px solid; border-right:rgb(167,198,223) 1px solid; border-bottom:rgb(167,198,223) 1px solid; padding-bottom:0.5ex; padding-top:0.5ex; padding-left:0.5ex; border-left:rgb(167,198,223) 1px solid; padding-right:0.5ex; background-color:rgb(255,255,255)"> Maximum number of semaphores system-wide</td> 
   <td style="border-top:rgb(167,198,223) 1px solid; border-right:rgb(167,198,223) 1px solid; border-bottom:rgb(167,198,223) 1px solid; padding-bottom:0.5ex; padding-top:0.5ex; padding-left:0.5ex; border-left:rgb(167,198,223) 1px solid; padding-right:0.5ex; background-color:rgb(255,255,255)"> ceil((max_connections + autovacuum_max_workers + max_worker_processes + 5) / 16) * 17&nbsp;plus room for other applications</td> 
  </tr> 
  <tr> 
   <td style="border-top:rgb(167,198,223) 1px solid; border-right:rgb(167,198,223) 1px solid; border-bottom:rgb(167,198,223) 1px solid; padding-bottom:0.5ex; padding-top:0.5ex; padding-left:0.5ex; border-left:rgb(167,198,223) 1px solid; padding-right:0.5ex; background-color:rgb(255,255,255)"> SEMMSL</td> 
   <td style="border-top:rgb(167,198,223) 1px solid; border-right:rgb(167,198,223) 1px solid; border-bottom:rgb(167,198,223) 1px solid; padding-bottom:0.5ex; padding-top:0.5ex; padding-left:0.5ex; border-left:rgb(167,198,223) 1px solid; padding-right:0.5ex; background-color:rgb(255,255,255)"> Maximum number of semaphores per set</td> 
   <td style="border-top:rgb(167,198,223) 1px solid; border-right:rgb(167,198,223) 1px solid; border-bottom:rgb(167,198,223) 1px solid; padding-bottom:0.5ex; padding-top:0.5ex; padding-left:0.5ex; border-left:rgb(167,198,223) 1px solid; padding-right:0.5ex; background-color:rgb(255,255,255)"> at least 17</td> 
  </tr> 
  <tr> 
   <td style="border-top:rgb(167,198,223) 1px solid; border-right:rgb(167,198,223) 1px solid; border-bottom:rgb(167,198,223) 1px solid; padding-bottom:0.5ex; padding-top:0.5ex; padding-left:0.5ex; border-left:rgb(167,198,223) 1px solid; padding-right:0.5ex; background-color:rgb(255,255,255)"> SEMMAP</td> 
   <td style="border-top:rgb(167,198,223) 1px solid; border-right:rgb(167,198,223) 1px solid; border-bottom:rgb(167,198,223) 1px solid; padding-bottom:0.5ex; padding-top:0.5ex; padding-left:0.5ex; border-left:rgb(167,198,223) 1px solid; padding-right:0.5ex; background-color:rgb(255,255,255)"> Number of entries in semaphore map</td> 
   <td style="border-top:rgb(167,198,223) 1px solid; border-right:rgb(167,198,223) 1px solid; border-bottom:rgb(167,198,223) 1px solid; padding-bottom:0.5ex; padding-top:0.5ex; padding-left:0.5ex; border-left:rgb(167,198,223) 1px solid; padding-right:0.5ex; background-color:rgb(255,255,255)"> see text</td> 
  </tr> 
  <tr> 
   <td style="border-top:rgb(167,198,223) 1px solid; border-right:rgb(167,198,223) 1px solid; border-bottom:rgb(167,198,223) 1px solid; padding-bottom:0.5ex; padding-top:0.5ex; padding-left:0.5ex; border-left:rgb(167,198,223) 1px solid; padding-right:0.5ex; background-color:rgb(255,255,255)"> SEMVMX</td> 
   <td style="border-top:rgb(167,198,223) 1px solid; border-right:rgb(167,198,223) 1px solid; border-bottom:rgb(167,198,223) 1px solid; padding-bottom:0.5ex; padding-top:0.5ex; padding-left:0.5ex; border-left:rgb(167,198,223) 1px solid; padding-right:0.5ex; background-color:rgb(255,255,255)"> Maximum value of semaphore</td> 
   <td style="border-top:rgb(167,198,223) 1px solid; border-right:rgb(167,198,223) 1px solid; border-bottom:rgb(167,198,223) 1px solid; padding-bottom:0.5ex; padding-top:0.5ex; padding-left:0.5ex; border-left:rgb(167,198,223) 1px solid; padding-right:0.5ex; background-color:rgb(255,255,255)"> at least 1000 (The default is often 32767; do not change unless necessary)</td> 
  </tr> 
 </tbody> 
</table>

[http_blog.163.com_dazuiba_008_blog_static_363349812016314739538]: http://blog.163.com/dazuiba_008/blog/static/363349812016314739538/