First of all, it is necessary to introduce the use of RAID card, about the cache problem also has a personal understanding: the production system of the physical disk configuration is mostly RAID5, before the frequent encounter disk IO at some time extremely slow to keep pace, a little write volume, disk Utils can soar to more than 80% The last discovery is the performance impact of the RAID card's mode change; the battery of the general RAID card is charged and discharged to protect the battery, the general time in 90 days of charge and discharge, discharging time is different (not verified this, feel 1-2 hours). RAID card Battery Discharge when there is a default policy to turn off the raid mode "write back" using "write through" write back: RAID-enabled cache in system-to-disk data interaction, when writing data is turned on, Its performance can be increased by an order of magnitude (generally raid cards are equipped with 512M, 1G cache) Write Throug: Do not enable Raidcache, directly have the disk for data interaction, but the reading performance is good; battery discharge this feature is enabled to prevent the write Back and no RAID card battery situation, the system power loss results in the final, considering the IDC room situation we have turned on the battery discharge state also forced to open the cache policy to solve the short-time on the write performance of the excessive gap to see if the current mode, the following is the write ThrougForced Open method
/opt/megaraid/megacli/megacli64-ldsetprop Cachedbadbbu-lall-aall if bad BBU on Adapter 0, VD 0 (t Arget id:0/opt/megaraid/megacli/megacli64-ldsetprop wb-lall-aall 0, VD 0 (target id:0 /opt/megaraid/megacli/megacli64-ldgetprop-cache-l0-A0 if bad BBU
After opening
Using MEGACLI under ESXiESXCLI software Vib install-v/tmp/vmware-esx-megacli-8.07.07.vib--no-sig-check/opt/lsi/megacli/megacli-ldinfo-lall-aallForce modify RAID card to Wb:cd/opt/lsi/megacli//opt/lsi/megacli/megacli-ldsetprop cachedbadbbu-lall-aall/opt/lsi/megacli/ Megacli-ldsetprop wb-lall-aall/opt/lsi/megacli/megacli-ldgetprop-cache-l0-a0
MEGACLI Monitoring RAID Disk health information
