在維護fusion 和sas 盤組成flashcache 的過程中遇到一些錯誤記錄下來。
#flashcache_create -p back -b 16k cachedev /dev/fioa /dev/sdc1
cachedev cachedev, ssd_devname /dev/fioa, disk_devname /dev/sdc1 cache mode WRITE_BACK
block_size 32, md_block_size 8, cache_size 0
flashcache_create: Valid Flashcache already exists on /dev/fioa
flashcache_create: Use flashcache_destroy first and then create again /dev/fioa
<b>錯誤提示說明:</b>
<b> fioa 上已經有建立了flashcache了要重新建立flahcache 必須使用 flashcache_destroy 指令 删除原有的裝置 /dev/fioa </b>
flashcache_destroy -f /dev/fioa
flashcache_create -p back -b 16k cachedev /dev/fioa /dev/sdc1
#flashcache_create -p back -b 16k cachedev /dev/fioa /dev/sdb1
cachedev cachedev, ssd_devname /dev/fioa, disk_devname /dev/sdb1 cache mode WRITE_BACK
Flashcache metadata will use 768MB of your 96840MB main memory
device-mapper: reload ioctl failed: Device or resource busy
Command failed
echo 0 4688222208 flashcache /dev/sdb1 /dev/fioa cachedev 1 2 32 0 512 8 | dmsetup create cachedev failed
flashcache_create 無法在已經mount的檔案系統上再做cache。
解決的辦法:
<b>umount /dev/sdb1</b>
<b>然後按照重新執行 flashcache_create 指令。 </b>
正确的做法是對/dev/sdb分區,建立ext4或者ext3,xfs 檔案系統,然後利用flashcache_create 将ssd裝置和檔案系統映射起來構成/dev/mapper/cache,将該flashcache用ext4 ext3 xfs 的方式mount起來。