From mboxrd@z Thu Jan 1 00:00:00 1970 From: Youenn Gestin Subject: strange mirror write perf Date: Sun, 19 Mar 2017 16:14:03 +0100 Message-ID: References: <6ec5f2dbefa2b7489d9f39d4833d5113@grim-is-a-geek.fr> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Return-path: In-Reply-To: <6ec5f2dbefa2b7489d9f39d4833d5113@grim-is-a-geek.fr> Sender: linux-raid-owner@vger.kernel.org To: linux-raid@vger.kernel.org List-Id: linux-raid.ids Hello, I'm encountering a drop of write performance after creating a mirror with two whole disk ( sdc and sdd ) and i'm not able to find where it come from: Perf before : abyss ~ # dd bs=1M count=2024 if=/dev/zero of=/dev/sdd conv=fdatasync 2024+0 records in 2024+0 records out 2122317824 bytes (2,1 GB, 2,0 GiB) copied, 14,1238 s, 150 MB/s abyss ~ # dd bs=1M count=2024 if=/dev/zero of=/dev/sdc conv=fdatasync 2024+0 records in 2024+0 records out 2122317824 bytes (2,1 GB, 2,0 GiB) copied, 14,7046 s, 144 MB/s Creating the mirror : abyss ~ # mdadm --create --verbose /dev/md/md6to --level=1 --raid-devices=2 /dev/sdc /dev/sdd mdadm: Note: this array has metadata at the start and may not be suitable as a boot device. If you plan to store '/boot' on this device please ensure that your boot-loader understands md/v1.x metadata, or use --metadata=0.90 mdadm: size set to 5860391488K mdadm: automatically enabling write-intent bitmap on large array Continue creating array? y mdadm: Defaulting to version 1.2 metadata mdadm: array /dev/md/md6to started. Perf after : abyss ~ # dd bs=1M count=2024 if=/dev/zero of=/dev/md/md6to conv=fdatasync 2024+0 records in 2024+0 records out 2122317824 bytes (2,1 GB, 2,0 GiB) copied, 21,1528 s, 100 MB/s I've also tried with a mirror created on two partition and the result was the same. I tried with a LVM mirror, the drop of performance was not so important : abyss ~ # vgcreate data_vg /dev/sdc Physical volume "/dev/sdc" successfully created. Volume group "data_vg" successfully created abyss ~ # vgextend data_vg /dev/sdd Physical volume "/dev/sdd" successfully created. Volume group "data_vg" successfully extended abyss ~ # vgs VG #PV #LV #SN Attr VSize VFree data_vg 2 0 0 wz--n- 10,92t 10,92t abyss ~ # lvcreate -L 50G -m1 -n lv_mirror data_vg Logical volume "lv_mirror" created. abyss ~ # dd bs=1M count=2024 if=/dev/zero of=/dev/data_vg/lv_mirror conv=fdatasync 2024+0 records in 2024+0 records out 2122317824 bytes (2,1 GB, 2,0 GiB) copied, 16,3757 s, 130 MB/s I didn't notice anything wrong while launching the dd test and watching top. Here are the information from asked https://raid.wiki.kernel.org/index.php/Asking_for_help abyss lsdrv # smartctl --xall /dev/sdc smartctl 6.5 2016-05-07 r4318 [x86_64-linux-4.10.2-gentoo] (local build) Copyright (C) 2002-16, Bruce Allen, Christian Franke, www.smartmontools.org === START OF INFORMATION SECTION === Model Family: Western Digital Red Device Model: WDC WD60EFRX-68L0BN1 Serial Number: WD-WX11D76EPFJV LU WWN Device Id: 5 0014ee 2b88cbb3d Firmware Version: 82.00A82 User Capacity: 6 001 175 126 016 bytes [6,00 TB] Sector Sizes: 512 bytes logical, 4096 bytes physical Rotation Rate: 5700 rpm Device is: In smartctl database [for details use: -P show] ATA Version is: ACS-2, ACS-3 T13/2161-D revision 3b SATA Version is: SATA 3.1, 6.0 Gb/s (current: 3.0 Gb/s) Local Time is: Fri Mar 17 14:41:32 2017 CET SMART support is: Available - device has SMART capability. SMART support is: Enabled AAM feature is: Unavailable APM feature is: Unavailable Rd look-ahead is: Enabled Write cache is: Enabled ATA Security is: Disabled, frozen [SEC2] Wt Cache Reorder: Enabled === START OF READ SMART DATA SECTION === SMART overall-health self-assessment test result: PASSED General SMART Values: Offline data collection status: (0x00) Offline data collection activity was never started. Auto Offline Data Collection: Disabled. Self-test execution status: ( 0) The previous self-test routine completed without error or no self-test has ever been run. Total time to complete Offline data collection: ( 8144) seconds. Offline data collection capabilities: (0x7b) SMART execute Offline immediate. Auto Offline data collection on/off support. Suspend Offline collection upon new command. Offline surface scan supported. Self-test supported. Conveyance Self-test supported. Selective Self-test supported. SMART capabilities: (0x0003) Saves SMART data before entering power-saving mode. Supports SMART auto save timer. Error logging capability: (0x01) Error logging supported. General Purpose Logging supported. Short self-test routine recommended polling time: ( 2) minutes. Extended self-test routine recommended polling time: ( 735) minutes. Conveyance self-test routine recommended polling time: ( 5) minutes. SCT capabilities: (0x303d) SCT Status supported. SCT Error Recovery Control supported. SCT Feature Control supported. SCT Data Table supported. SMART Attributes Data Structure revision number: 16 Vendor Specific SMART Attributes with Thresholds: ID# ATTRIBUTE_NAME FLAGS VALUE WORST THRESH FAIL RAW_VALUE 1 Raw_Read_Error_Rate POSR-K 200 200 051 - 0 3 Spin_Up_Time POS--K 208 208 021 - 8558 4 Start_Stop_Count -O--CK 100 100 000 - 12 5 Reallocated_Sector_Ct PO--CK 200 200 140 - 0 7 Seek_Error_Rate -OSR-K 200 200 000 - 0 9 Power_On_Hours -O--CK 100 100 000 - 274 10 Spin_Retry_Count -O--CK 100 253 000 - 0 11 Calibration_Retry_Count -O--CK 100 253 000 - 0 12 Power_Cycle_Count -O--CK 100 100 000 - 12 192 Power-Off_Retract_Count -O--CK 200 200 000 - 6 193 Load_Cycle_Count -O--CK 200 200 000 - 25 194 Temperature_Celsius -O---K 119 111 000 - 33 196 Reallocated_Event_Count -O--CK 200 200 000 - 0 197 Current_Pending_Sector -O--CK 200 200 000 - 0 198 Offline_Uncorrectable ----CK 100 253 000 - 0 199 UDMA_CRC_Error_Count -O--CK 200 200 000 - 0 200 Multi_Zone_Error_Rate ---R-- 100 253 000 - 0 ||||||_ K auto-keep |||||__ C event count ||||___ R error rate |||____ S speed/performance ||_____ O updated online |______ P prefailure warning General Purpose Log Directory Version 1 SMART Log Directory Version 1 [multi-sector log support] Address Access R/W Size Description 0x00 GPL,SL R/O 1 Log Directory 0x01 SL R/O 1 Summary SMART error log 0x02 SL R/O 5 Comprehensive SMART error log 0x03 GPL R/O 6 Ext. Comprehensive SMART error log 0x06 SL R/O 1 SMART self-test log 0x07 GPL R/O 1 Extended self-test log 0x09 SL R/W 1 Selective self-test log 0x10 GPL R/O 1 SATA NCQ Queued Error log 0x11 GPL R/O 1 SATA Phy Event Counters log 0x21 GPL R/O 1 Write stream error log 0x22 GPL R/O 1 Read stream error log 0x30 GPL,SL R/O 9 IDENTIFY DEVICE data log 0x80-0x9f GPL,SL R/W 16 Host vendor specific log 0xa0-0xa7 GPL,SL VS 16 Device vendor specific log 0xa8-0xb6 GPL,SL VS 1 Device vendor specific log 0xb7 GPL,SL VS 54 Device vendor specific log 0xbd GPL,SL VS 1 Device vendor specific log 0xc0 GPL,SL VS 1 Device vendor specific log 0xc1 GPL VS 93 Device vendor specific log 0xe0 GPL,SL R/W 1 SCT Command/Status 0xe1 GPL,SL R/W 1 SCT Data Transfer SMART Extended Comprehensive Error Log Version: 1 (6 sectors) No Errors Logged SMART Extended Self-test Log Version: 1 (1 sectors) No self-tests have been logged. [To run self-tests, use: smartctl -t] SMART Selective self-test log data structure revision number 1 SPAN MIN_LBA MAX_LBA CURRENT_TEST_STATUS 1 0 0 Not_testing 2 0 0 Not_testing 3 0 0 Not_testing 4 0 0 Not_testing 5 0 0 Not_testing Selective self-test flags (0x0): After scanning selected spans, do NOT read-scan remainder of disk. If Selective self-test is pending on power-up, resume after 0 minute delay. SCT Status Version: 3 SCT Version (vendor specific): 258 (0x0102) SCT Support Level: 1 Device State: Active (0) Current Temperature: 33 Celsius Power Cycle Min/Max Temperature: 32/41 Celsius Lifetime Min/Max Temperature: 17/41 Celsius Under/Over Temperature Limit Count: 0/0 Vendor specific: 01 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 SCT Temperature History Version: 2 Temperature Sampling Period: 1 minute Temperature Logging Interval: 1 minute Min/Max recommended Temperature: 0/60 Celsius Min/Max Temperature Limit: -41/85 Celsius Temperature History Size (Index): 478 (193) Index Estimated Time Temperature Celsius 194 2017-03-17 06:44 32 ************* ... ..(464 skipped). .. ************* 181 2017-03-17 14:29 32 ************* 182 2017-03-17 14:30 33 ************** ... ..( 10 skipped). .. ************** 193 2017-03-17 14:41 33 ************** SCT Error Recovery Control: Read: 70 (7,0 seconds) Write: 70 (7,0 seconds) Device Statistics (GP/SMART Log 0x04) not supported SATA Phy Event Counters (GP Log 0x11) ID Size Value Description 0x0001 2 0 Command failed due to ICRC error 0x0002 2 13 R_ERR response for data FIS 0x0003 2 0 R_ERR response for device-to-host data FIS 0x0004 2 13 R_ERR response for host-to-device data FIS 0x0005 2 0 R_ERR response for non-data FIS 0x0006 2 0 R_ERR response for device-to-host non-data FIS 0x0007 2 0 R_ERR response for host-to-device non-data FIS 0x0008 2 0 Device-to-host non-data FIS retries 0x0009 2 15 Transition from drive PhyRdy to drive PhyNRdy 0x000a 2 30 Device-to-host register FISes sent due to a COMRESET 0x000b 2 8 CRC errors within host-to-device FIS 0x000d 2 5 Non-CRC errors within host-to-device FIS 0x000f 2 8 R_ERR response for host-to-device data FIS, CRC 0x0012 2 0 R_ERR response for host-to-device non-data FIS, CRC 0x8000 4 318448 Vendor specific ------------------------------------------------------------------------------- abyss lsdrv # smartctl --xall /dev/sdd smartctl 6.5 2016-05-07 r4318 [x86_64-linux-4.10.2-gentoo] (local build) Copyright (C) 2002-16, Bruce Allen, Christian Franke, www.smartmontools.org === START OF INFORMATION SECTION === Model Family: Western Digital Red Device Model: WDC WD60EFRX-68L0BN1 Serial Number: WD-WX41D964EZK9 LU WWN Device Id: 5 0014ee 263752a6e Firmware Version: 82.00A82 User Capacity: 6 001 175 126 016 bytes [6,00 TB] Sector Sizes: 512 bytes logical, 4096 bytes physical Rotation Rate: 5700 rpm Device is: In smartctl database [for details use: -P show] ATA Version is: ACS-2, ACS-3 T13/2161-D revision 3b SATA Version is: SATA 3.1, 6.0 Gb/s (current: 6.0 Gb/s) Local Time is: Fri Mar 17 14:41:57 2017 CET SMART support is: Available - device has SMART capability. SMART support is: Enabled AAM feature is: Unavailable APM feature is: Unavailable Rd look-ahead is: Enabled Write cache is: Enabled ATA Security is: Disabled, frozen [SEC2] Wt Cache Reorder: Enabled === START OF READ SMART DATA SECTION === SMART overall-health self-assessment test result: PASSED General SMART Values: Offline data collection status: (0x00) Offline data collection activity was never started. Auto Offline Data Collection: Disabled. Self-test execution status: ( 0) The previous self-test routine completed without error or no self-test has ever been run. Total time to complete Offline data collection: ( 9344) seconds. Offline data collection capabilities: (0x7b) SMART execute Offline immediate. Auto Offline data collection on/off support. Suspend Offline collection upon new command. Offline surface scan supported. Self-test supported. Conveyance Self-test supported. Selective Self-test supported. SMART capabilities: (0x0003) Saves SMART data before entering power-saving mode. Supports SMART auto save timer. Error logging capability: (0x01) Error logging supported. General Purpose Logging supported. Short self-test routine recommended polling time: ( 2) minutes. Extended self-test routine recommended polling time: ( 746) minutes. Conveyance self-test routine recommended polling time: ( 5) minutes. SCT capabilities: (0x303d) SCT Status supported. SCT Error Recovery Control supported. SCT Feature Control supported. SCT Data Table supported. SMART Attributes Data Structure revision number: 16 Vendor Specific SMART Attributes with Thresholds: ID# ATTRIBUTE_NAME FLAGS VALUE WORST THRESH FAIL RAW_VALUE 1 Raw_Read_Error_Rate POSR-K 200 200 051 - 0 3 Spin_Up_Time POS--K 100 253 021 - 0 4 Start_Stop_Count -O--CK 100 100 000 - 5 5 Reallocated_Sector_Ct PO--CK 200 200 140 - 0 7 Seek_Error_Rate -OSR-K 100 253 000 - 0 9 Power_On_Hours -O--CK 100 100 000 - 246 10 Spin_Retry_Count -O--CK 100 253 000 - 0 11 Calibration_Retry_Count -O--CK 100 253 000 - 0 12 Power_Cycle_Count -O--CK 100 100 000 - 5 192 Power-Off_Retract_Count -O--CK 200 200 000 - 1 193 Load_Cycle_Count -O--CK 200 200 000 - 19 194 Temperature_Celsius -O---K 121 116 000 - 31 196 Reallocated_Event_Count -O--CK 200 200 000 - 0 197 Current_Pending_Sector -O--CK 200 200 000 - 0 198 Offline_Uncorrectable ----CK 100 253 000 - 0 199 UDMA_CRC_Error_Count -O--CK 200 200 000 - 0 200 Multi_Zone_Error_Rate ---R-- 100 253 000 - 0 ||||||_ K auto-keep |||||__ C event count ||||___ R error rate |||____ S speed/performance ||_____ O updated online |______ P prefailure warning General Purpose Log Directory Version 1 SMART Log Directory Version 1 [multi-sector log support] Address Access R/W Size Description 0x00 GPL,SL R/O 1 Log Directory 0x01 SL R/O 1 Summary SMART error log 0x02 SL R/O 5 Comprehensive SMART error log 0x03 GPL R/O 6 Ext. Comprehensive SMART error log 0x04 GPL,SL R/O 8 Device Statistics log 0x06 SL R/O 1 SMART self-test log 0x07 GPL R/O 1 Extended self-test log 0x09 SL R/W 1 Selective self-test log 0x0c GPL R/O 2048 Pending Defects log 0x10 GPL R/O 1 SATA NCQ Queued Error log 0x11 GPL R/O 1 SATA Phy Event Counters log 0x21 GPL R/O 1 Write stream error log 0x22 GPL R/O 1 Read stream error log 0x30 GPL,SL R/O 9 IDENTIFY DEVICE data log 0x80-0x9f GPL,SL R/W 16 Host vendor specific log 0xa0-0xa7 GPL,SL VS 16 Device vendor specific log 0xa8-0xb6 GPL,SL VS 1 Device vendor specific log 0xb7 GPL,SL VS 54 Device vendor specific log 0xbd GPL,SL VS 1 Device vendor specific log 0xc0 GPL,SL VS 1 Device vendor specific log 0xc1 GPL VS 93 Device vendor specific log 0xe0 GPL,SL R/W 1 SCT Command/Status 0xe1 GPL,SL R/W 1 SCT Data Transfer SMART Extended Comprehensive Error Log Version: 1 (6 sectors) No Errors Logged SMART Extended Self-test Log Version: 1 (1 sectors) No self-tests have been logged. [To run self-tests, use: smartctl -t] SMART Selective self-test log data structure revision number 1 SPAN MIN_LBA MAX_LBA CURRENT_TEST_STATUS 1 0 0 Not_testing 2 0 0 Not_testing 3 0 0 Not_testing 4 0 0 Not_testing 5 0 0 Not_testing Selective self-test flags (0x0): After scanning selected spans, do NOT read-scan remainder of disk. If Selective self-test is pending on power-up, resume after 0 minute delay. SCT Status Version: 3 SCT Version (vendor specific): 258 (0x0102) SCT Support Level: 1 Device State: Active (0) Current Temperature: 31 Celsius Power Cycle Min/Max Temperature: 30/36 Celsius Lifetime Min/Max Temperature: 16/36 Celsius Under/Over Temperature Limit Count: 0/0 Vendor specific: 01 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 SCT Temperature History Version: 2 Temperature Sampling Period: 1 minute Temperature Logging Interval: 1 minute Min/Max recommended Temperature: 0/60 Celsius Min/Max Temperature Limit: -41/85 Celsius Temperature History Size (Index): 478 (434) Index Estimated Time Temperature Celsius 435 2017-03-17 06:44 30 *********** ... ..(463 skipped). .. *********** 421 2017-03-17 14:28 30 *********** 422 2017-03-17 14:29 31 ************ ... ..( 11 skipped). .. ************ 434 2017-03-17 14:41 31 ************ SCT Error Recovery Control: Read: 70 (7,0 seconds) Write: 70 (7,0 seconds) Device Statistics (GP Log 0x04) Page Offset Size Value Flags Description 0x01 ===== = = === == General Statistics (rev 2) == 0x01 0x008 4 5 --- Lifetime Power-On Resets 0x01 0x010 4 246 --- Power-on Hours 0x01 0x018 6 23708519208 --- Logical Sectors Written 0x01 0x020 6 24687968 --- Number of Write Commands 0x01 0x028 6 11729201720 --- Logical Sectors Read 0x01 0x030 6 22155003 --- Number of Read Commands 0x03 ===== = = === == Rotating Media Statistics (rev 1) == 0x03 0x008 4 246 --- Spindle Motor Power-on Hours 0x03 0x010 4 43 --- Head Flying Hours 0x03 0x018 4 21 --- Head Load Events 0x03 0x020 4 0 --- Number of Reallocated Logical Sectors 0x03 0x028 4 0 --- Read Recovery Attempts 0x03 0x030 4 0 --- Number of Mechanical Start Failures 0x04 ===== = = === == General Errors Statistics (rev 1) == 0x04 0x008 4 0 --- Number of Reported Uncorrectable Errors 0x04 0x010 4 0 --- Resets Between Cmd Acceptance and Completion 0x05 ===== = = === == Temperature Statistics (rev 1) == 0x05 0x008 1 31 --- Current Temperature 0x05 0x010 1 30 --- Average Short Term Temperature 0x05 0x018 1 - --- Average Long Term Temperature 0x05 0x020 1 36 --- Highest Temperature 0x05 0x028 1 19 --- Lowest Temperature 0x05 0x030 1 33 --- Highest Average Short Term Temperature 0x05 0x038 1 30 --- Lowest Average Short Term Temperature 0x05 0x040 1 - --- Highest Average Long Term Temperature 0x05 0x048 1 - --- Lowest Average Long Term Temperature 0x05 0x050 4 0 --- Time in Over-Temperature 0x05 0x058 1 60 --- Specified Maximum Operating Temperature 0x05 0x060 4 0 --- Time in Under-Temperature 0x05 0x068 1 0 --- Specified Minimum Operating Temperature 0x06 ===== = = === == Transport Statistics (rev 1) == 0x06 0x008 4 22 --- Number of Hardware Resets 0x06 0x010 4 3 --- Number of ASR Events 0x06 0x018 4 0 --- Number of Interface CRC Errors |||_ C monitored condition met ||__ D supports DSN |___ N normalized value SATA Phy Event Counters (GP Log 0x11) ID Size Value Description 0x0001 2 0 Command failed due to ICRC error 0x0002 2 0 R_ERR response for data FIS 0x0003 2 0 R_ERR response for device-to-host data FIS 0x0004 2 0 R_ERR response for host-to-device data FIS 0x0005 2 0 R_ERR response for non-data FIS 0x0006 2 0 R_ERR response for device-to-host non-data FIS 0x0007 2 0 R_ERR response for host-to-device non-data FIS 0x0008 2 0 Device-to-host non-data FIS retries 0x0009 2 2 Transition from drive PhyRdy to drive PhyNRdy 0x000a 2 4 Device-to-host register FISes sent due to a COMRESET 0x000b 2 0 CRC errors within host-to-device FIS 0x000d 2 0 Non-CRC errors within host-to-device FIS 0x000f 2 0 R_ERR response for host-to-device data FIS, CRC 0x0012 2 0 R_ERR response for host-to-device non-data FIS, CRC 0x8000 4 318477 Vendor specific abyss lsdrv # mdadm --examine /dev/sdc /dev/sdc: Magic : a92b4efc Version : 1.2 Feature Map : 0x1 Array UUID : 183ad93e:c604b817:7099c950:12d36bab Name : abyss:md6to (local to host abyss) Creation Time : Mon Mar 13 22:11:47 2017 Raid Level : raid1 Raid Devices : 2 Avail Dev Size : 11720783024 (5588.90 GiB 6001.04 GB) Array Size : 5860391488 (5588.90 GiB 6001.04 GB) Used Dev Size : 11720782976 (5588.90 GiB 6001.04 GB) Data Offset : 262144 sectors Super Offset : 8 sectors Unused Space : before=262064 sectors, after=48 sectors State : clean Device UUID : b55a87f4:15d145d1:19979cc5:e1eafc32 Internal Bitmap : 8 sectors from superblock Update Time : Fri Mar 17 14:24:32 2017 Bad Block Log : 512 entries available at offset 32 sectors Checksum : b949b844 - correct Events : 9925 Device Role : Active device 1 Array State : AA ('A' == active, '.' == missing, 'R' == replacing) ----------------------------------------------------------------------------- abyss lsdrv # mdadm --examine /dev/sdd /dev/sdd: Magic : a92b4efc Version : 1.2 Feature Map : 0x1 Array UUID : 183ad93e:c604b817:7099c950:12d36bab Name : abyss:md6to (local to host abyss) Creation Time : Mon Mar 13 22:11:47 2017 Raid Level : raid1 Raid Devices : 2 Avail Dev Size : 11720783024 (5588.90 GiB 6001.04 GB) Array Size : 5860391488 (5588.90 GiB 6001.04 GB) Used Dev Size : 11720782976 (5588.90 GiB 6001.04 GB) Data Offset : 262144 sectors Super Offset : 8 sectors Unused Space : before=262064 sectors, after=48 sectors State : clean Device UUID : ddbae969:eae9cb91:fb7fa642:1932781a Internal Bitmap : 8 sectors from superblock Update Time : Fri Mar 17 14:24:32 2017 Bad Block Log : 512 entries available at offset 32 sectors Checksum : 53b76159 - correct Events : 9925 Device Role : Active device 0 Array State : AA ('A' == active, '.' == missing, 'R' == replacing) ----------------------------------------------------------------------------- abyss lsdrv # mdadm --detail /dev/md127 /dev/md127: Version : 1.2 Creation Time : Mon Mar 13 22:11:47 2017 Raid Level : raid1 Array Size : 5860391488 (5588.90 GiB 6001.04 GB) Used Dev Size : 5860391488 (5588.90 GiB 6001.04 GB) Raid Devices : 2 Total Devices : 2 Persistence : Superblock is persistent Intent Bitmap : Internal Update Time : Fri Mar 17 14:24:32 2017 State : clean Active Devices : 2 Working Devices : 2 Failed Devices : 0 Spare Devices : 0 Name : abyss:md6to (local to host abyss) UUID : 183ad93e:c604b817:7099c950:12d36bab Events : 9925 Number Major Minor RaidDevice State 0 8 48 0 active sync /dev/sdd 1 8 32 1 active sync /dev/sdc ----------------------------------------------------------------------------- abyss lsdrv # python2.7 lsdrv PCI [hptiop] 01:00.0 RAID bus controller: HighPoint Technologies, Inc. Device 3520 (rev 09) └scsi 0:0:0:0 HPT VD0-0 {} └sda 8.19t [8:0] Partitioned (gpt) └sda1 8.19t [8:1] ext4 {7262b140-e026-4b53-bc6b-2ac1c1cc4538} └Mounted as /dev/sda1 @ /mnt PCI [ahci] 00:11.0 SATA controller: Advanced Micro Devices, Inc. [AMD] FCH SATA Controller [AHCI mode] (rev 40) ├scsi 1:0:0:0 ATA OCZ-VERTEX4 {OCZ-9NYS802X56U11736} │└sdb 238.47g [8:16] Partitioned (dos) │ └sdb1 238.47g [8:17] ext4 {6de79b5d-dc44-4362-86af-b483fbbe1c65} │ └Mounted as /dev/sdb1 @ / ├scsi 2:0:0:0 ATA WDC WD60EFRX-68L {WD-WX11D76EPFJV} │└sdc 5.46t [8:32] MD raid1 (1/2) (w/ sdd) in_sync 'abyss:md6to' {183ad93e-c604-b817-7099-c95012d36bab} │ └md127 5.46t [9:127] MD v1.2 raid1 (2) clean {183ad93e:c604b817:7099c950:12d36bab} │ Empty/Unknown ├scsi 3:0:0:0 ATA WDC WD60EFRX-68L {WD-WX41D964EZK9} │└sdd 5.46t [8:48] MD raid1 (0/2) (w/ sdc) in_sync 'abyss:md6to' {183ad93e-c604-b817-7099-c95012d36bab} │ └md127 5.46t [9:127] MD v1.2 raid1 (2) clean {183ad93e:c604b817:7099c950:12d36bab} │ Empty/Unknown ├scsi 4:x:x:x [Empty] ----------------------------------------------------------------------------- abyss lsdrv # cat /proc/mdstat Personalities : [raid1] [raid10] [raid6] [raid5] [raid4] md127 : active raid1 sdd[0] sdc[1] 5860391488 blocks super 1.2 [2/2] [UU] bitmap: 0/44 pages [0KB], 65536KB chunk unused devices: ----------------------------------------------------------------------------- abyss lsdrv # mdadm --version mdadm - v4.0 - 2017-01-09 ----------------------------------------------------------------------------- abyss lsdrv # uname -a Linux abyss 4.10.2-gentoo #2 SMP Mon Mar 13 21:46:37 CET 2017 x86_64 AMD A8-5600K APU with Radeon(tm) HD Graphics AuthenticAMD GNU/Linux Thanks for your help. Youenn.