How can i spot or test drives in a raid (raid 10) on my backup server that is running centos?

Thanks

software raid?

For hardware raid you may not be able to see the individual drives.

Thanks, this is software raid

A few things I have noticed are clunking noises, slower drive reads and writes compared to normal and odd repeated I/O or SATA type messages written in your logs.

My admin told me one drive had died. I ran the commands but it all looks good. How can I find out what drive has failed?

cat /proc/mdstat
Personalities : [raid6] [raid5] [raid4]
md0 : active raid5 sdd[5](F) sdb[0] sde[4] sdc[1]
8790799296 blocks super 1.0 level 5, 64k chunk, algorithm 2 [4/3] [UU_U]

unused devices: <none>

/usr/sbin/smartctl -H /dev/sda
smartctl 5.42 2011-10-20 r3458 [x86_64-linux-2.6.18-194.3.1.el5.centos.plus] (local build)
Copyright (C) 2002-11 by Bruce Allen, http://smartmontools.sourceforge.net

=== START OF READ SMART DATA SECTION ===
SMART overall-health self-assessment test result: PASSED

grep "" /sys/block/sd*/device/state
/sys/block/sda/device/state:running
/sys/block/sdb/device/state:running
/sys/block/sdc/device/state:running
/sys/block/sdd/device/state:running
/sys/block/sde/device/state:running

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Thanks

It does not look good. Your raid is missing one drive. The "(F)" means drive sdd is faulty.

You can run smartctl -H on other drives than sda.

Ok so I've ordered a new drive to replace the faulty one.

How would one go about replacing the drive, also how is it possible to know which one I need to physically pull out of the machine?

Could I replace the disk without powering off the machine?

Does the raid need to be rebuilt afterwards?

The reason I'm asking is because I've ordered the replacement drive to the data center and I need to tell the engineer what drive to replace. I'm not sure if this is box has hot swap or not.

Thanks