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Task #5770

Updated by Nico Schottelius almost 4 years ago

* Detailed explanation 
 * Including commands of megacli 
 * Including motivation 

 h2. Disk handling 

 Our servers are using Perc H700 or H800 disk controllers. The tool **megacli** can be used to manage them. 

 h3. Handling foreign configuration 

 When plugging a disk into a server that was configured / used in a different server before, we need to clear the previous configuration. 

 Listing all known foreign configuration using **megacli -CfgForeign -Scan -aALL**. 

 Remove/clear the foreign configuration using 

 <pre> 
 # for instance -L5 -a0 or -L2 -a1 
 megacli -DiscardPreservedCache -L<slot-or-ID> -a<Controller> 

 </pre> 

 h3. Removal of a disk 

 If a (dead or intact) disk is being removed from the system, the system will HANG on the next reboot, complaining about it missing. For that reason AFTER removing a disk, we need to "clear the cache": 

 <pre> 

 # Get list of caches that need to be cleared 
 megacli -GetPreservedCacheList -aALL 

 # Clear cache: -L0 -a1 
 megacli -DiscardPreservedCache -L<??> -a<controller> 

 </pre> 

 h2. How to move an OSD (Disk, SSD) to another server 

 * Use ceph-osd-stop-disable from ungleich tools to stop / disable the OSD 
 * Clear the raid controller information 
 * Insert disk into new host 
 * Clear the foreign configuration (megacli) 
 * [add it to the system with megacli] 
 * OSD should automatically come up afterwards 
 ** Check using **ceph osd tree**

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