Q & A NFS 遠端目錄無法卸載 Umount a NFS directory with the error: device is busy 當遭遇某些異常情況時,原先的 NFS 目錄可能無法用指令 umount 正常卸載,且主機因為還在營運生產中,不能執行重開機時,下述的指令可能會有幫助。 # 檢查那些程序及用戶使用該目錄 fuser -m -v lsof | grep lsof +f -- # 刪除無效的程序 fuser -i -k fuser -km umount # 以上都無效,可重啟 NFS Client daemon,但其他 NFS 目錄也會被迫中斷。 service netfs stop service netfs start # 網友提供的另一個方法 umount -l umount -f 檢查線上 NFS 掛載參數, nfs 版本 cat /proc/mounts | grep nfs Can't mount remotely Linux host on AIX Try to run the following commands on your AIX. nfso -o nfs_use_reserved_ports=1 nfso -o portcheck=1 Remove Shared Memory # see all shared memory segments # status: dest -> destroyed # nattach: how many application being attached to the shared memory. ipcs -m ipcs -m -i # remove the shared memory segment ipcrm shm ipcrm -m CentOS Upgrade Kernel: linux-firmware package files conflicts 說明:要升級 CentOS 7.6 Kernel to CentOS 7.7,遇到 linux-firmware 套件衝突問題。 rpm -ivh kernel-3.10.0-1062.el7.x86_64.rpm warning: kernel-3.10.0-1062.el7.x86_64.rpm: Header V3 RSA/SHA256 Signature, key ID fd431d51: NOKEY error: Failed dependencies: linux-firmware >= 20190429-72 is needed by kernel-3.10.0-1062.el7.x86_64 rpm -ivh linux-firmware-20190429-72.gitddde598.el7.noarch.rpm kernel-3.10.0-1062.el7.x86_64.rpm warning: linux-firmware-20190429-72.gitddde598.el7.noarch.rpm: Header V3 RSA/SHA256 Signature, key ID f4a80eb5: NOKEY warning: kernel-3.10.0-1062.el7.x86_64.rpm: Header V3 RSA/SHA256 Signature, key ID fd431d51: NOKEY Preparing... ################################# [100%] file /usr/lib/firmware/amd-ucode/microcode_amd_fam17h.bin from install of linux-firmware-20190429-72.gitddde598.el7.noarch conflicts with file from package linux-firmware-20180911-69.git85c5d90.el7.noarch file /usr/lib/firmware/amd-ucode/microcode_amd_fam17h.bin.asc from install of linux-firmware-20190429-72.gitddde598.el7.noarch conflicts with file from package linux-firmware-20180911-69.git85c5d90.el7.noarch # Solution: rpm -Uvh linux-firmware-20190429-72.gitddde598.el7.noarch.rpm rpm -ivh kernel-3.10.0-1062.el7.x86_64.rpm Adjust reserved 5% of disk space by default Reduce it to 2% sudo tune2fs -m2 /dev/sda1 指令 du 與 df 顯示的使用空間有很大的落差 一般來說,問題通常是 df 的使用空間遠大於 du 的使用空間。 原因是 du 不會對開啟中的檔案進行計算,如果有開啟中的大檔案佔用目錄,du 是無法發現的。 解決方法: 使用指令 lsof /path/to/dir 檢查目錄裡有沒有程式正在執行中 確實關閉程式後再用 du 檢查一遍