#RAID MONITOR LINUX UPDATE#
#RAID MONITOR LINUX SOFTWARE#

RAID 5 gives us more usable storage than mirroring does, but at the price of some performance. That means a RAID 6 can recover from two failed members. RAID 6 is similar to RAID 5 but sets aside two disks’ worth for parity data. If two or more drives crash, we’ll have to restore the whole thing from backups. RAID 5 can recover and rebuild with no data loss if one drive dies. Similarly, the RAID’s performance will be limited by its slowest member.

Adding a larger drive won’t get us more space, as the RAID will just use the size of the smallest member. This means we usually want to build our RAID out of a set of drives of identical size and speed.

It is not all kept on one drive, however instead, the parity data is striped across all of the devices along with the filesystem data. RAID 5 sets aside one drive’s worth of space for checksum parity data. In practice, we can add several more, though rarely more than ten are used. RAID 5 requires at least three equal-size drives to function. Parity allows our RAIDs to reconstruct data stored on failed drives. You can then submit a rating below the article.Instead of storing complete copies of our data, we can save space by storing parity data. To leave feedback, log in to your IONOS account by clicking on the login button at the top right. Your feedback helps us to further improve our services. Errors will also be reported in the system log file./mdadm -monitor -syslog -delay=300 /dev/md0 -daemonise Did this article help you? If an event occurs, an email will be sent to the address specified in /etc/nf. In this example, the option -daemonise runs the monitoring program continuously in the background, checking the array every 300 seconds. By adding an email address to the /etc/nf file, error messages will be sent to the address if there is a disk failure. The mdadm utility can also be run as a demon.

#RAID MONITOR LINUX UPDATE#

If there is a missing disk, the output is similar to the following: mdadm -D /dev/md0 /dev/md0: Version : 00.90.00 Creation Time : Thu Aug 21 12:22:43 2003 Raid Level : raid1 Array Size : 102208 (99.81 MiB 104.66 MB) Device Size : 102208 (99.81 MiB 104.66 MB) Raid Devices : 2 Total Devices : 1 Preferred Minor : 0 Persistence : Superblock is persistent Update Time : Fri Oct 15 06:25:45 2004 State : dirty, no-errors Active Devices : 1 Working Devices : 1 Failed Devices : 0 Spare Devices : 0 Number Major Minor RaidDevice State 0 0 0 0 faulty removed 1 3 1 1 active sync /dev/sda1 UUID : f9401842:995dc86c:b4102b57:f2996278 Monitor RAID mdadm -D /dev/md1 /dev/md1: Version : 0.90 Creation Time : Tue Sep 11 21:33:24 2012 Raid Level : raid1 Array Size : 4194240 (4.00 GiB 4.29 GB) Used Dev Size : 4194240 (4.00 GiB 4.29 GB) Raid Devices : 2 Total Devices : 2 Preferred Minor : 1 Persistence : Superblock is persistent Update Time : Wed Jun 10 11:11:05 2015 State : clean Active Devices : 2 Working Devices : 2 Failed Devices : 0 Spare Devices : 0 UUID : 2db35cef:bde058e8:1f51fb89:78ee93fe Events : 0.251 Number Major Minor RaidDevice State 0 8 1 0 active sync /dev/sda1 1 8 17 1 active sync /dev/sdb1 The command mdadm -D /dev/md1 provides detailed information about the md1 array.Īn example of the output for a working RAID array is below. With only one disk up for each array, you can see that something is wrong here. If a disk is down (not functioning), the output looks similar to the following: cat /proc/mdstat Personalities : read_ahead 1024 sectors md0 : active raid1 sda1 102208 blocks md2 : active raid1 sda3 262016 blocks md1 : active raid1 sda2 119684160 blocks unused devices: A U means that the respective device is up, or functional. On the second line for each device, the state of each partition is shown within square brackets at the end. The example shows three RAID arrays (md0, md1, md2). The following commands are exemplary and must be adapted accordingly!īelow is an example of the output if both disks are present and correctly mounted: cat /proc/mdstat Personalities : read_ahead 1024 sectors md2 : active raid1 sda3 sdb3 262016 blocks md1 : active raid1 sda2 sdb2 119684160 blocks md0 : active raid1 sda1 sdb1 102208 blocks unused devices:

#RAID MONITOR LINUX SOFTWARE#

You can check the status of a software RAID array with the command cat /proc/mdstat.

Raid monitor linux