自宅環境のARMボードにZabbix-agentを導入したところ掲題のようなエラーメッセージが。
問題のメッセージ
16042:20150401:233544.949 Starting Zabbix Agent [dns02.kometch.local]. Zabbix 2.4.4 (revision 52341). 16042:20150401:233544.951 using configuration file: /etc/zabbix/zabbix_agentd.conf 16042:20150401:233544.952 cannot allocate shared memory of size 175768: [22] Invalid argument 16042:20150401:233544.953 cannot allocate shared memory for collector
確認環境：
$ lsb_release -a No LSB modules are available. Distributor ID:Ubuntu Description:Ubuntu 14.04.2 LTS Release:14.04 Codename:trusty
どうやら共有メモリが確保出来無いらしい。
ということでKernelパラメータをチューニングする必要があるそうです。
その前に幾つか値の確認
$ ipcs -l ------ Shared Memory Limits -------- max number of segments = 4096 max seg size (kbytes) = 0 max total shared memory (kbytes) = 16777216 min seg size (bytes) = 1 ------ Semaphore Limits -------- max number of arrays = 1024 max semaphores per array = 250 max semaphores system wide = 32000 max ops per semop call = 128 semaphore max value = 32767 ------ Messages Limits -------- max queues system wide = 32000 max size of message (bytes) = 65536 default max size of queue (bytes) = 65536
$ sudo sysctl -a | grep shm kernel.shm_rmid_forced = 0 kernel.shmall = 4194304 kernel.shmmax = 0 kernel.shmmni = 4096
対応方法
sysctl.confに以下のパラメータを追記する。
kernel.shmall = 2097152 kernel.shmmax = 33554432
そして有効にして、再度値を確認する。
$ sudo sysctl -p $ sudo sysctl -a | grep shm kernel.shm_rmid_forced = 0 kernel.shmall = 2097152 kernel.shmmax = 33554432 kernel.shmmni = 4096 $ sudo ipcs -l ------ Shared Memory Limits -------- max number of segments = 4096 max seg size (kbytes) = 32768 max total shared memory (kbytes) = 8388608 min seg size (bytes) = 1 ------ Semaphore Limits -------- max number of arrays = 1024 max semaphores per array = 250 max semaphores system wide = 32000 max ops per semop call = 128 semaphore max value = 32767 ------ Messages Limits -------- max queues system wide = 32000 max size of message (bytes) = 65536 default max size of queue (bytes) = 65536
zabbix-agentを起動させ、問題なく起動することを確認する。（logの確認など）
$ sudo ipcs -m ------ Shared Memory Segments -------- key shmid owner perms bytes nattch status 0x6c011121 65536 zabbix 600 175768 6
今更ですが（2020年2月18日：追記）
この件ってZabbix wikiでも専用のページが用意されていたんですね。
Configuration of shared memory for zabbix_server daemon
General information
If you need to use significantly increased values of caches (CacheSize, HistoryCacheSize, HistoryTextCacheSize, TrendCacheSize) for zabbix_server daemon then you have to configure (increase) kernel parameters.
Some operating systems, like FreeBSD, require increased kernel parameters to start zabbix_server daemon even with the default configuration file. For example: zabbix_server requires 36 Mbytes total (defaulf Zabbix caches), but FreeBSD by default allows to allocate only 8192*4096 = 32 Mbytes
Note that if other programs are using shared memory as well (PostgreSQL for example), you will have to coordinate the size settings between them. Note that the amount of total size of shared memory (shmall) is measured in Pages and one page size is the value of PAGE_SIZE (normally 4096 bytes).