dm-x device causing confusion;replacing harddrive son software raid.

Below is the dump when I do lsblkcat /proc/mdstatlmsetup -ls. So sde is dying and I would like to replace it. What i'm confused is, in lsblk it shows sde is part of md3 (software raid). but when I cat mdstat its showing a bunch of lm-x. Google a little bit and it seems lm-x are part of device mapper in kernal used by LVM.

Anyways, what i'm asking is, since it's a production machine. I want to be extra caution with it. Normally I would just do mdadm /dev/md3 -f /dev/sde1 to flag the disk as failure then do /dev/md3 -r /dev/sde to remove the disk from array. Then after that I would do a hotswap. In this case it's dm-12. Is there any extra steps and procedure that I need to be careful of?

Also please don't ask me why I make it a hardware raid (which is a hell lot simpler) it wasn't my idea, and the prev guy left me with 0 documentation )=.

Thanks

[root@beryl ~]# lsblk NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT sda 8:0 0 465.8G 0 disk └─WDC_WD5003ABYX-01WERA1_WD-WMAYP5328002 253:1 0 465.8G 0 mpath └─WDC_WD5003ABYX-01WERA1_WD-WMAYP5328002p1 253:10 0 465.8G 0 part └─md3 9:3 0 1.8T 0 raid10 /data sdb 8:16 0 465.8G 0 disk └─WDC_WD5003ABYX-01WERA1_WD-WMAYP5361211 253:0 0 465.8G 0 mpath └─WDC_WD5003ABYX-01WERA1_WD-WMAYP5361211p1 253:6 0 465.8G 0 part └─md3 9:3 0 1.8T 0 raid10 /data sdc 8:32 0 465.8G 0 disk └─WDC_WD5003ABYX-01WERA1_WD-WMAYP5365544 253:2 0 465.8G 0 mpath └─WDC_WD5003ABYX-01WERA1_WD-WMAYP5365544p1 253:9 0 465.8G 0 part └─md3 9:3 0 1.8T 0 raid10 /data sdd 8:48 0 465.8G 0 disk └─WDC_WD5003ABYX-01WERA0_WD-WMAYP1373520 253:3 0 465.8G 0 mpath └─WDC_WD5003ABYX-01WERA0_WD-WMAYP1373520p1 253:11 0 465.8G 0 part └─md3 9:3 0 1.8T 0 raid10 /data sde 8:64 0 465.8G 0 disk └─WDC_WD5003ABYX-01WERA1_WD-WMAYP5283827 253:4 0 465.8G 0 mpath └─WDC_WD5003ABYX-01WERA1_WD-WMAYP5283827p1 253:12 0 465.8G 0 part └─md3 9:3 0 1.8T 0 raid10 /data sdf 8:80 0 465.8G 0 disk └─WDC_WD5003ABYX-01WERA1_WD-WMAYP5360357 253:5 0 465.8G 0 mpath └─WDC_WD5003ABYX-01WERA1_WD-WMAYP5360357p1 253:13 0 465.8G 0 part └─md3 9:3 0 1.8T 0 raid10 /data sdg 8:96 0 465.8G 0 disk └─WDC_WD5003ABYX-01WERA1_WD-WMAYP5122698 253:7 0 465.8G 0 mpath └─WDC_WD5003ABYX-01WERA1_WD-WMAYP5122698p1 253:14 0 465.8G 0 part └─md3 9:3 0 1.8T 0 raid10 /data sdh 8:112 0 465.8G 0 disk └─WDC_WD5003ABYX-01WERA1_WD-WMAYP5329057 253:8 0 465.8G 0 mpath └─WDC_WD5003ABYX-01WERA1_WD-WMAYP5329057p1 253:15 0 465.8G 0 part └─md3 9:3 0 1.8T 0 raid10 /data sdi 8:128 0 74.5G 0 disk ├─sdi1 8:129 0 200M 0 part │ └─md0 9:0 0 200M 0 raid1 /boot ├─sdi2 8:130 0 16.6G 0 part │ └─md1 9:1 0 16.6G 0 raid1 / ├─sdi3 8:131 0 4G 0 part [SWAP] └─sdi4 8:132 0 53.7G 0 part └─md2 9:2 0 53.7G 0 raid1 /opt sdj 8:144 0 74.5G 0 disk ├─sdj1 8:145 0 200M 0 part │ └─md0 9:0 0 200M 0 raid1 /boot ├─sdj2 8:146 0 16.6G 0 part │ └─md1 9:1 0 16.6G 0 raid1 / ├─sdj3 8:147 0 4G 0 part [SWAP] └─sdj4 8:148 0 53.7G 0 part └─md2 9:2 0 53.7G 0 raid1 /opt [root@beryl ~]# cat /proc/mdstat Personalities : [raid1] [raid10] md2 : active raid1 sdi4[0] sdj4[1] 56314808 blocks super 1.2 [2/2] [UU] md3 : active raid10 dm-15[6] dm-14[7] dm-13[4] dm-12[5] dm-11[3] dm-10[0] dm-9[2] dm-6[1] 1953017344 blocks super 1.2 32K chunks 2 near-copies [8/8] [UUUUUUUU] md0 : active raid1 sdi1[0] sdj1[1] 204788 blocks super 1.0 [2/2] [UU] md1 : active raid1 sdi2[0] sdj2[1] 17406908 blocks super 1.1 [2/2] [UU] bitmap: 1/1 pages [4KB], 65536KB chunk unused devices: <none> [root@beryl ~]# dmsetup ls WDC_WD5003ABYX-01WERA1_WD-WMAYP5329057 (253:8) WDC_WD5003ABYX-01WERA1_WD-WMAYP5360357p1 (253:13) WDC_WD5003ABYX-01WERA1_WD-WMAYP5122698 (253:7) WDC_WD5003ABYX-01WERA1_WD-WMAYP5283827p1 (253:12) WDC_WD5003ABYX-01WERA1_WD-WMAYP5365544p1 (253:9) WDC_WD5003ABYX-01WERA1_WD-WMAYP5328002p1 (253:10) WDC_WD5003ABYX-01WERA1_WD-WMAYP5283827 (253:4) WDC_WD5003ABYX-01WERA1_WD-WMAYP5361211 (253:0) WDC_WD5003ABYX-01WERA1_WD-WMAYP5329057p1 (253:15) WDC_WD5003ABYX-01WERA1_WD-WMAYP5328002 (253:1) WDC_WD5003ABYX-01WERA1_WD-WMAYP5365544 (253:2) WDC_WD5003ABYX-01WERA1_WD-WMAYP5361211p1 (253:6) WDC_WD5003ABYX-01WERA0_WD-WMAYP1373520 (253:3) WDC_WD5003ABYX-01WERA1_WD-WMAYP5122698p1 (253:14) WDC_WD5003ABYX-01WERA0_WD-WMAYP1373520p1 (253:11) WDC_WD5003ABYX-01WERA1_WD-WMAYP5360357 (253:5)