Hot Swap - Raid Soft
This guide will show you the steps required to hotswap a disk on a server using software RAID.
Requirements
Hot swapping is only possible on the server ranges mHG, HG, and bHG.
To carry out the various steps of this guide, you must:
- Have a server that is mHG, HG, or bHG.
- Have a server using software RAID (with a LSI card).
- Have access to SSH (Linux) or RDP (Windows).
- Have the sas2ircu utility installed beforehand. (Available via the search engine broadcom)
In this guide, we will assume that you have received an alert for the disk /dev/sdb, Serial Number K4GW439B, which is defective and you want to hotswap it.
For this we will need the Enclosure ID, the Slot ID, and the Serial Number of the disk that needs to be replaced.
In Linux
Step 1: Identify the disk
We have been notified that our SDB disk is defective, so we will test it and check its Serial Number.
root@ns3054662:/home# smartctl -a /dev/sdb smartctl 6.4 2014-10-07 r4002 [x86_64-linux-3.14.32-xxxx-grs-ipv6-64] (local build) Copyright (C) 2002-14, Bruce Allen, Christian Franke, www.smartmontools.org === START OF INFORMATION SECTION === Vendor: HGST Product: HUS726040ALS210 Revision: A907 Compliance: SPC-4 User Capacity: 4,000,787,030,016 bytes [4.00 TB] Logical block size: 512 bytes LB provisioning type: unreported, LBPME=0, LBPRZ=0 Rotation Rate: 7200 rpm Form Factor: 3.5 inches Logical Unit id: 0x5000cca25d3155bc Serial number: K4GW439B Device type: disk Transport protocol: SAS (SPL-3) Local Time is: Mon Nov 21 14:23:43 2016 CET SMART support is: Available - device has SMART capability. SMART support is: Enabled Temperature Warning: Enabled === START OF READ SMART DATA SECTION === SMART Health Status: OK Current Drive Temperature: 34 C Drive Trip Temperature: 85 C Manufactured in week 44 of year 2016 Specified cycle count over device lifetime: 50000 Accumulated start-stop cycles: 9 Specified load-unload count over device lifetime: 600000 Accumulated load-unload cycles: 14 Elements in grown defect list: 0 Vendor (Seagate) cache information Blocks sent to initiator = 2305525022720 Error counter log: Errors Corrected by Total Correction Gigabytes Total ECC rereads/ errors algorithm processed uncorrected fast | delayed rewrites corrected invocations [10^9 bytes] errors read: 0 572 0 22548 77 4.725 5580 write: 0 0 0 19548 196 17.344 2569 Non-medium error count: 0 SMART Self-test log Num Test Status segment LifeTime LBA_first_err [SK ASC ASQ] Description number (hours) # 1 Background short Completed - 6 - [- - -] # 2 Background short Completed - 4 - [- - -] # 3 Background short Completed - 4 - [- - -] # 4 Background short Completed - 4 - [- - -] # 5 Background short Completed - 1 - [- - -] Long (extended) Self Test duration: 34237 seconds [570.6 minutes]
Or more simply :
root@ns3054662:/home# smartctl -a /dev/sdb | grep Serial Serial number: K4GW439B
We find that our SDB is actually defective (uncorrected errors in our case), and that its serial number corresponds to the alert received (via Datacentre or any other monitoring tool).
So we can move on to the next step of retrieving the Enclosure ID and Slot ID information from the disk to be replaced.
Step 2: Locate the position of the disk
In order to retrieve the Slot ID and Enclosure ID from our defective SDB disk, we will need the sas2ircu software to be installed on the server.
First, we will check that the disk is connected via a LSI card.
root@ns3054662:/home# lspci | grep -i LSI 81:00.0 Serial Attached SCSI controller: LSI Logic / Symbios Logic SAS2004 PCI-Express Fusion-MPT SAS-2 [Spitfire] (rev 03) We can see that we have a LSI card. We must now determine the ID of this LSI card.
root@ns3054662:/home# ./sas2ircu list LSI Corporation SAS2 IR Configuration Utility. Version 5.00.00.00 (2010.02.09) Copyright (c) 2009 LSI Corporation. All rights reserved. Adapter Vendor Device SubSys SubSys Index Type ID ID Pci Address Ven ID Dev ID ----- ------------ ------ ------ ----------------- ------ ------ 0 SAS2004 1000h 70h 00h:81h:00h:00h 1000h 3010h SAS2IRCU: Utility Completed Successfully.
The index corresponds to the ID, so our map has the index / ID 0.
With this information, we can now retrieve the Slot ID and Enclosure ID for our SDB disk, Serial Number K4GW439B.
root@ns3054662:/home# ./sas2ircu 0 display | grep -B 7 -A 2 K4GW439B Device is a Hard disk Enclosure # : 1 Slot # : 3 State : Available (AVL) Manufacturer : HGST Model Number : HUS726040ALS210 Firmware Revision : A907 Serial No : K4GW439B Protocol : SAS Drive Type : SAS_HDD
With this command we directly retrieve the information for our SDB disk.
Of course, K4GW439B will be replaced by the Serial Number of the drive to be replaced, and 0 by the ID of the RAID card concerned.
From our example above, the disk has the Enclosure ID of 1, and the Slot ID of 3.
Step 3: Turn on the disk indicator
With the information retrieved in the previous steps, we can turn on the LED of the defective disk for replacement with the command : ./sas2ircu 0 locate EncID:SlotID on
root@ns3054662:/home# ./sas2ircu 0 locate 1:3 on LSI Corporation SAS2 IR Configuration Utility. Version 5.00.00.00 (2010.02.09) Copyright (c) 2009 LSI Corporation. All rights reserved. SAS2IRCU: LOCATE command completed successfully. SAS2IRCU: Command LOCATE Completed Successfully. SAS2IRCU: Utility Completed Successfully.
In this example, we have used the information gathered from the previous steps where 0 is the Index of the RAID card, 1 is the Enclosure ID, and 3 is the Slot ID.
You can turn off the blinking LED of the disk by replacing "on" with "off" in the command.
Now we have to move on to the last step of removing the defective disk from the software RAID before the datacentre intervention begins.
Step 4: Remove the disk from the RAID
Before removing the defective disk from the RAID, we must set it to Faulty if this is not already the case (We are using the SDB disk in our example).
We will first look at the state of the RAID.
root@ns3054662:/home# cat /proc/mdstat Personalities : [linear] [raid0] [raid1] [raid10] [raid6] [raid5] [raid4] [multipath] [faulty] md2 : active raid1 sda2[0] sdb2[1] 3885385728 blocks super 1.2 [2/2] [UU] bitmap: 0/29 pages [0KB], 65536KB chunk md1 : active raid1 sdb1[1] sda1[0] 20971456 blocks [2/2] [UU] unused devices:
We see that our defective SDB disk is part of md1 and md2 (sdb1 and sdb2).
We will now set the disk to Faulty (sdb1 in md1, and sdb2 in md2 respectively).
root@ns3054662:/home# mdadm --manage /dev/md1 --set-faulty /dev/sdb1 mdadm: set /dev/sdb1 faulty in /dev/md1
root@ns3054662:/home# mdadm --manage /dev/md2 --set-faulty /dev/sdb2 mdadm: set /dev/sdb2 faulty in /dev/md2
The RAID status is checked again.
root@ns3054662:/home# cat /proc/mdstat Personalities : [linear] [raid0] [raid1] [raid10] [raid6] [raid5] [raid4] [multipath] [faulty] md2 : active raid1 sda2[0] sdb2[1](F) 3885385728 blocks super 1.2 [2/1] [U_] bitmap: 0/29 pages [0KB], 65536KB chunk md1 : active raid1 sdb1[2](F) sda1[0] 20971456 blocks [2/1] [U_] unused devices:
sdb1 and sdb2 are now showing as faulty (F).
Now we can remove the disks from the software RAID.
root@ns3054662:/home# mdadm --manage /dev/md1 --remove /dev/sdb1 mdadm: hot removed /dev/sdb1 from /dev/md1
root@ns3054662:/home# mdadm --manage /dev/md2 --remove /dev/sdb2 mdadm: hot removed /dev/sdb2 from /dev/md2
Then we check one last time that the disk is no longer present.
root@ns3054662:/home# cat /proc/mdstat Personalities : [linear] [raid0] [raid1] [raid10] [raid6] [raid5] [raid4] [multipath] [faulty] md2 : active raid1 sda2[0] 3885385728 blocks super 1.2 [2/1] [U_] bitmap: 0/29 pages [0KB], 65536KB chunk md1 : active raid1 sda1[0] 20971456 blocks [2/1] [U_] unused devices:
We are now ready to have the defective disk replaced by a datacentre technician.
As we have prepared the server for the intervention, the new disk will take the SDB name, and all that is left to do is to rebuild the software RAID.
In Windows
The Windows-based guide will be similar to the replacement guide for Linux. We will use the same utility: sas2ircu, and the commands in Windows are the same as it is in Linux.
It is important to run the powershell terminal as an administrator to avoid errors.
In this guide, we will assume that you have received an alert for the disk /dev/sdb, Serial Number K4G187WB, which is defective and you want to hotswap it.
For this we will need the Enclosure ID, the Slot ID, and the Serial Number of the disk that needs to be replaced.
Step 1: Identify the disk
We have been notified that our SDB disk is defective, so we will test it and check its Serial Number.
The disk used for our guide is not actually defective, but for demonstration purposes, we will perform the following procedure as if it is.
The Serial Number of the disk corresponds to the alert received (via the Datacentre or any other monitoring tool).
So we can move on to the next step of retrieving the Enclosure ID and Slot ID information from the disk to be replaced.
Step 2: Locate the position of the disk
We will now retrieve the Slot ID and Enclosure ID from our defective SDB disk. To do this, we will need the sas2ircu software installed on the server.
First, determine the ID of the LSI RAID card present in the server.
So we have our LSI card which has index / ID "0".
With this information, we can now find the Slot ID and Enclosure ID of our SDB disk, Serial Number K4G187WB.
The example Serial Number K4G187WB will of course be replaced by yours.
You can also search for information by listing the disks in a more general way.
We can see that our Serial Number K4G187WB has the Enclosure ID of 1, and the Slot ID of 1 (2nd disk of the list in this case).
Step 3: Turn on the disk indicator
With the information retrieved in the previous steps, we can turn on the LED of the defective disk for replacement with the following command : .\sas2ircu.exe ID locate EncID:SlotID on
You can turn off the blinking LED of the disk after it has been replaced by using "off" instead of "on" in the previous command.
Now we have to move on to the last step of removing the defective disk from the software RAID before the datacentre intervention begins.
Step 4: Remove the disk from the RAID
Soon...
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