5.9.9. Day to Day Management of RAID Arrays
5.9.9. Day to Day Management of RAID Arrays There is little that needs to be done to keep a RAID array operating. As long as no hardware problems crop up, the array should function just as if it were a single physical disk drive. However, just as a system administrator should periodically check the status of all disk drives on the system, the RAID arrays' status should be checked as well. 5.9.9.1. Checking Array Status With /proc/mdstat The file /proc/mdstat is the easiest way to check on the status of all RAID arrays on a particular system. Here is a sample mdstat (view with the command cat /proc/mdstat ): On this system, there are three RAID arrays (all RAID 1). Each RAID array has its own section in /proc/mdstat and contains the following information: The RAID array device name (not including the /dev/ part) The status of the RAID array The RAID array's RAID level The physical partitions that currently make up the array (followed by the partition's array unit number) The size of the array The number of configured devices versus the number of operative devices in the array The status of each configured device in the array ( U meaning the device is OK, and _ indicating that the device has failed)
Personalities : [raid1] read_ahead 1024 sectors md1 : active raid1 hda3[0] hdc3[1] 522048 blocks [2/2] [UU] md0 : active raid1 hda2[0] hdc2[1] 4192896 blocks [2/2] [UU] md2 : active raid1 hda1[0] hdc1[1] 128384 blocks [2/2] [UU] unused devices: <none>