Open Infrastructure

• Table of contents
• Disk handling
  • Handling foreign configuration
  • Removal of a disk
• How to move an OSD (Disk, SSD) to another server

• Detailed explanation
• Including commands of megacli
• Including motivation

Disk handling¶

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

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

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

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":

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

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

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