systemctl status taosd 一直无法启动，网上各种找原因也没不行
1，删除data；
2，卸载重装
rmtaos
3，修改日志目录
vi /etc/taos/taos.cfg
最后发现用最原始的命令会给出直接的错误
如本来是
● taosd.service - TDengine server service
Loaded: loaded (/etc/systemd/system/taosd.service; enabled; vendor preset: disabled)
Active: failed (Result: start-limit) since 四 2022-09-08 14:38:39 CST; 11s ago
Process: 9837 ExecStart=/usr/bin/taosd (code=exited, status=255)
Process: 9828 ExecStartPre=/usr/local/taos/bin/startPre.sh (code=exited, status=0/SUCCESS)
Main PID: 9837 (code=exited, status=255)
9月 08 14:38:39 localhost.localdomain systemd[1]: Unit taosd.service entered failed state.
9月 08 14:38:39 localhost.localdomain systemd[1]: taosd.service failed.
9月 08 14:38:39 localhost.localdomain systemd[1]: taosd.service holdoff time over, scheduling restart.
9月 08 14:38:39 localhost.localdomain systemd[1]: Stopped TDengine server service.
9月 08 14:38:39 localhost.localdomain systemd[1]: start request repeated too quickly for taosd.service
9月 08 14:38:39 localhost.localdomain systemd[1]: Failed to start TDengine server service.
9月 08 14:38:39 localhost.localdomain systemd[1]: Unit taosd.service entered failed state.
9月 08 14:38:39 localhost.localdomain systemd[1]: taosd.service failed.
那么执行/usr/bin/taosd错误如下：
09/08 15:09:14.406291 00046820 UTL fail to load apoll url
09/08 15:09:14.406415 00046820 UTL load from cfg file /etc/taos/taos.cfg success
09/08 15:09:14.406439 00046820 UTL failed to load env file: .env
09/08 15:09:14.406452 00046820 UTL load from env variables cfg success
09/08 15:09:14.407276 00046820 UTL fail to load apoll url
09/08 15:09:14.407385 00046820 UTL load from cfg file /etc/taos/taos.cfg success
09/08 15:09:14.407435 00046820 UTL failed to load env file: .env
09/08 15:09:14.407453 00046820 UTL load from env variables cfg success
09/08 15:09:14.407647 00046820 UTL global config
09/08 15:09:14.407662 00046820 UTL =================================================================
09/08 15:09:14.407674 00046820 UTL default firstEp localhost:6030
09/08 15:09:14.407685 00046820 UTL default secondEp localhost:6030
09/08 15:09:14.407695 00046820 UTL default fqdn localhost
09/08 15:09:14.407708 00046820 UTL default serverPort 6030
09/08 15:09:14.407719 00046820 UTL default tempDir /tmp
09/08 15:09:14.407730 00046820 UTL default minimalTmpDirGB 1.00
09/08 15:09:14.407758 00046820 UTL default shellActivityTimer 3
09/08 15:09:14.407766 00046820 UTL default compressMsgSize -1
09/08 15:09:14.407773 00046820 UTL default compressColData -1
09/08 15:09:14.407781 00046820 UTL default queryPolicy 1
09/08 15:09:14.407788 00046820 UTL default querySmaOptimize 0
09/08 15:09:14.407795 00046820 UTL default queryPlannerTrace 0
09/08 15:09:14.407802 00046820 UTL default smlChildTableName
09/08 15:09:14.407808 00046820 UTL default smlTagName _tag_null
09/08 15:09:14.407815 00046820 UTL default smlDataFormat 1
09/08 15:09:14.407822 00046820 UTL default numOfTaskQueueThreads 4
09/08 15:09:14.407829 00046820 UTL cfg_file dataDir /opt/data/taos/data
09/08 15:09:14.407837 00046820 UTL default minimalDataDirGB 2.00
09/08 15:09:14.407850 00046820 UTL default supportVnodes 16
09/08 15:09:14.407861 00046820 UTL default maxShellConns 50000
09/08 15:09:14.407872 00046820 UTL default statusInterval 1
09/08 15:09:14.407882 00046820 UTL default minSlidingTime 10
09/08 15:09:14.407893 00046820 UTL default minIntervalTime 1
09/08 15:09:14.407903 00046820 UTL default maxNumOfDistinctRes 10000000
09/08 15:09:14.407913 00046820 UTL default countAlwaysReturnValue 1
09/08 15:09:14.407924 00046820 UTL default queryBufferSize -1
09/08 15:09:14.407934 00046820 UTL default printAuth 0
09/08 15:09:14.407945 00046820 UTL default multiProcess 0
09/08 15:09:14.407955 00046820 UTL default mnodeShmSize 20972544
09/08 15:09:14.407965 00046820 UTL default vnodeShmSize 104858624
09/08 15:09:14.407976 00046820 UTL default qnodeShmSize 41944064
09/08 15:09:14.407986 00046820 UTL default snodeShmSize 41944064
09/08 15:09:14.407996 00046820 UTL default bnodeShmSize 41944064
09/08 15:09:14.408008 00046820 UTL default numOfShmThreads 1
09/08 15:09:14.408019 00046820 UTL default numOfRpcThreads 4
09/08 15:09:14.408030 00046820 UTL default numOfCommitThreads 4
09/08 15:09:14.408041 00046820 UTL default numOfMnodeReadThreads 1
09/08 15:09:14.408052 00046820 UTL default numOfVnodeQueryThreads 16
09/08 15:09:14.408064 00046820 UTL default numOfVnodeStreamThreads 4
09/08 15:09:14.408074 00046820 UTL default numOfVnodeFetchThreads 4
09/08 15:09:14.408085 00046820 UTL default numOfVnodeWriteThreads 8
09/08 15:09:14.408096 00046820 UTL default numOfVnodeSyncThreads 16
09/08 15:09:14.408106 00046820 UTL default numOfVnodeRsmaThreads 8
09/08 15:09:14.408117 00046820 UTL default numOfQnodeQueryThreads 16
09/08 15:09:14.408128 00046820 UTL default numOfQnodeFetchThreads 4
09/08 15:09:14.408138 00046820 UTL default numOfSnodeSharedThreads 2
09/08 15:09:14.408149 00046820 UTL default numOfSnodeUniqueThreads 2
09/08 15:09:14.408161 00046820 UTL default rpcQueueMemoryAllowed 1664782745
09/08 15:09:14.408174 00046820 UTL default monitor 1
09/08 15:09:14.408186 00046820 UTL default monitorInterval 30
09/08 15:09:14.408197 00046820 UTL default monitorFqdn
09/08 15:09:14.408208 00046820 UTL default monitorPort 6043
09/08 15:09:14.408219 00046820 UTL default monitorMaxLogs 100
09/08 15:09:14.408231 00046820 UTL default monitorComp 0
09/08 15:09:14.408243 00046820 UTL default telemetryReporting 1
09/08 15:09:14.408253 00046820 UTL default telemetryInterval 43200
09/08 15:09:14.408265 00046820 UTL default telemetryServer telemetry.taosdata.com
09/08 15:09:14.408275 00046820 UTL default telemetryPort 80
09/08 15:09:14.408286 00046820 UTL default transPullupInterval 2
09/08 15:09:14.408298 00046820 UTL default mqRebalanceInterval 2
09/08 15:09:14.408309 00046820 UTL default ttlUnit 86400
09/08 15:09:14.408319 00046820 UTL default ttlPushInterval 86400
09/08 15:09:14.408331 00046820 UTL default uptimeInterval 300
09/08 15:09:14.408342 00046820 UTL default udf 1
09/08 15:09:14.408353 00046820 UTL default configDir /etc/taos
09/08 15:09:14.408364 00046820 UTL default scriptDir /etc/taos
09/08 15:09:14.408375 00046820 UTL cfg_file logDir /opt/data/taos/log/
09/08 15:09:14.408387 00046820 UTL default minimalLogDirGB 1.00
09/08 15:09:14.408400 00046820 UTL default numOfLogLines 10000000
09/08 15:09:14.408411 00046820 UTL default asyncLog 1
09/08 15:09:14.408422 00046820 UTL default logKeepDays 0
09/08 15:09:14.408434 00046820 UTL default debugFlag 0
09/08 15:09:14.408444 00046820 UTL default simDebugFlag 143
09/08 15:09:14.408455 00046820 UTL default tmrDebugFlag 131
09/08 15:09:14.408467 00046820 UTL default uDebugFlag 131
09/08 15:09:14.408478 00046820 UTL default rpcDebugFlag 131
09/08 15:09:14.408489 00046820 UTL default jniDebugFlag 131
09/08 15:09:14.408500 00046820 UTL default qDebugFlag 131
09/08 15:09:14.408512 00046820 UTL default cDebugFlag 131
09/08 15:09:14.408523 00046820 UTL default dDebugFlag 135
09/08 15:09:14.408547 00046820 UTL default vDebugFlag 135
09/08 15:09:14.408561 00046820 UTL default mDebugFlag 135
09/08 15:09:14.408610 00046820 UTL default wDebugFlag 135
09/08 15:09:14.408627 00046820 UTL default sDebugFlag 135
09/08 15:09:14.408640 00046820 UTL default tsdbDebugFlag 131
09/08 15:09:14.408651 00046820 UTL default tqDebugFlag 135
09/08 15:09:14.408662 00046820 UTL default fsDebugFlag 135
09/08 15:09:14.408674 00046820 UTL default udfDebugFlag 135
09/08 15:09:14.408685 00046820 UTL default smaDebugFlag 131
09/08 15:09:14.408696 00046820 UTL default idxDebugFlag 135
09/08 15:09:14.408707 00046820 UTL default tdbDebugFlag 131
09/08 15:09:14.408719 00046820 UTL default metaDebugFlag 135
09/08 15:09:14.408730 00046820 UTL default timezone Asia/Shanghai (CST, +0800)
09/08 15:09:14.408742 00046820 UTL default locale zh_CN.UTF-8
09/08 15:09:14.408753 00046820 UTL default charset UTF-8
09/08 15:09:14.408764 00046820 UTL default enableCoreFile 1
09/08 15:09:14.408775 00046820 UTL default numOfCores 8.00
09/08 15:09:14.408789 00046820 UTL default openMax 1024
09/08 15:09:14.408801 00046820 UTL default streamMax 16
09/08 15:09:14.408813 00046820 UTL default pageSizeKB 4
09/08 15:09:14.408824 00046820 UTL default totalMemoryKB 16257644
09/08 15:09:14.408835 00046820 UTL default os sysname Linux
09/08 15:09:14.408846 00046820 UTL default os nodename localhost.localdomain
09/08 15:09:14.408858 00046820 UTL default os release 3.10.0-957.el7.x86_64
09/08 15:09:14.408869 00046820 UTL default os version #1 SMP Thu Nov 8 23:39:32 UTC 2018
09/08 15:09:14.408880 00046820 UTL default os machine x86_64
09/08 15:09:14.408892 00046820 UTL default version 3.0.1.0
09/08 15:09:14.408903 00046820 UTL default compatible_version 3.0.0.0
09/08 15:09:14.408914 00046820 UTL default gitinfo 6a862b71990bdcceece800061138bcf58f4e37d7
09/08 15:09:14.408926 00046820 UTL default buildinfo Built at 2022-09-07 11:55
09/08 15:09:14.408936 00046820 UTL =================================================================
09/08 15:09:14.412693 00046820 DND start to init dnode env
09/08 15:09:14.412746 00046820 DND ERROR free disk size: 0.752548 GB, too little, require 2.000000 GB at least at least , quit
09/08 15:09:14.412876 00046820 DND ERROR failed to init dnode since No available disk
得出结论：空间不够