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Line 1: − ===Hard Drives – Raid===+ − From SME Server 7 a new feature was introduced - Automatic configuration of Software RAID 1, 5 or 6. RAID is a way of storing data on more than one hard drive at once, so that if one drive fails, the system will still function. − Your server will be automatically configured as follows:+ − * 1 Drive - Software RAID 1 (ready to accept a second drive). − * 2 Drives - Software RAID 1 − * 3 Drives - Software RAID 1 + 1 Hot-spare − * 4-6 Drives - Software RAID 5 + 1 Hot-spare − * 7+ Drives - Software RAID 6 + 1 Hot-spare − ====Hard Drive Layout====+ − Mirroring drives in the same IDE channel (eg. hda and hdb) is not desirable. If that channel goes out, you may loose both drives. Also, performance will suffer slightly. − The preferred method is to use the master location on each IDE channel (eg. hda and hdc). This will ensure that if you loose one channel, the other will still operate. It will also give you the best performance. + − In a 2 drive setups put each drive on a different IDE channel: + + − IDE 1 Master - Drive 1 <br />+ − IDE 1 Slave - CDROM <br /> − IDE 2 Master - Drive 2 <br /> − + − + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + − ====Adding another Hard Drive Later (Raid 1 array only)====+ − ENSURE THAT THE NEW DRIVE IS THE SAME SIZE OR LARGER AS THE CURRENT DRIVE(S)+ − * Shut down the machine − * Install drive as master on the second IDE channel (hdc) − * Boot up − * Log on as admin to get to the admin console − * Go to #5 Manage disk redundancy − It should tell you there if the drives are syncing up. Don't turn off the server until the sync is complete or it will start from the beginning again. When it is done syncing it will show a good working raid1.+ − If the Manage disk redundancy page gives the message "The free disk count must equal one" and "Manual intervention may be required", then you likely will have additional hard drives that need to be disconnected while the RAID is set up. An external USB drive will have this effect, and should be unplugged.+ + + + + + − Note: the addition of another drive is restricted to a RAID 1 scenario, i.e. two hard drives only (/dev/hda and /dev/hdc or their SATA equivalent). The addition of a third drive to a RAID 1 (i.e. a spare) is not recognized by the system [[bugzilla:6907]]+ − + + + + + + + + + + + + − + − + − + − + − + − + − + − + + + Line 80:
Line 163: − * All of this can be done while the server is up and running with the exception of #1. − * These instructions should work for any raid level you have as long as you have >= 2 drives − * If you have disabled lvm − # you don't need the pvresize or lvresize command − # the final line becomes ext2online -C0 /dev/md2 (or whatever / is mounted to) − + − + + + + + + + + + + + + − + − + − + − + − + − + − + − + − + − + − + − + + + Line 119:
Line 210: − * These instructions should work for any raid level you have as long as you have >= 2 drives − * If you have disabled lvm − # you don't need the pvresize or lvresize command − # the final line becomes ext2online -C0 /dev/md2 (or whatever / is mounted to) − + − Many on board hardware raid cards are in fact software RAID. Turn it off as cheap "fakeraid" cards aren't good. You will get better performance and reliability with Linux Software RAID (http://linux-ata.org/faq-sata-raid.html). Linux software RAID is fast and robust.+ − + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + Line 137:
Line 316: + + + + + + + + + + + + + + + + + + − + − + Line 151:
Line 348: − Current RAID status:+ − + − Personalities : [raid1]+ − md2 : active raid1 hda2[0] <-- NOTICE hdb2[#] is missing. Means hdb2[#] failed. + − 38973568 blocks [2/1] [U_]+ − + − md1 : active raid1 hda1[0] hdb1[1]+ − 104320 blocks [2/2] [UU]+ − + − unused devices: <none>+ − Only Some of the RAID devices are unclean. <-- NOTICE This message and + − Manual intervention may be required.</nowiki> <-- this message.+ Line 219:
Line 416: + + + − Your devices are likely to be different, and you may have more than two disks, including a hot standby, but will always be determined from the mdstat file. Once the raid resync has been started, the progress will be noted in mdstat. You can see this real time by:+ Line 253:
Line 453: + + + − + Line 262:
Line 465: − + Line 278:
Line 481: − sfdisk /dev/sdc < tmp.out+ − + − mdadm: /dev/sda2 appears to be part of a raid array:+ − level=raid1 devices=2 ctime=Fri Dec 18 13:17:49 2009+ − mdadm: /dev/sdb2 appears to be part of a raid array:+ − level=raid1 devices=2 ctime=Fri Dec 18 13:17:49 2009+ − Continue creating array? y+ − mdadm: array /dev/md2 started.+ − + − root# cat /proc/mdstat+ − Personalities : [raid0] [raid1] [raid5]+ − md2 : active raid5 sdb1[2] sda1[0]+ − 1048512 blocks level 5, 256k chunk, algorithm 2 [2/1] [U_]+ − [==>..................] recovery = 12.5% (132096/1048512) finish=0.8min speed=18870K/sec Line 304:
Line 506: − + Line 313:
Line 515: − + − root# cat /proc/mdstat+ − Personalities : [raid0] [raid1] [raid5]+ − md2 : active raid5 sdc1[2] sdb1[1] sda1[0]+ − 1048512 blocks super 0.91 level 5, 256k chunk, algorithm 2 [3/3] [UUU]+ − [==>..................] reshape = 12.5% (131520/1048512) finish=2.5min speed=5978K/sec − lvresize -l +100%FREE main/root+ − resize2fs /dev/main/root + − * If you have disabled lvm − # you don't need the pvresize or lvresize command − # the final line becomes resize2fs /dev/md2 (or whatever / is mounted to) − # More info: http://www.arkf.net/blog/?p=47 + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + − + + + +
no edit summary
{{Warning box| Please read this article before buying and deploying drives. https://raid.wiki.kernel.org/index.php/Timeout_Mismatch
The new type of SMR drives are NOT suitable for RAID arrays. Beware WD Red NAS drives, though recently they have made it clearer which models use SMR.
'''A drive failure can corrupt an entire array: RAID does not replace backup!'''}}
{{Note box| SME Servers RAID Options are largely automated, but even with the best laid plans things don't always go according to plan. See also: [[Raid:Manual Rebuild]], [[Raid:Growing]] and [[Hard Disk Partitioning]]. There is a wiki on the Linux software raid, you will find many [https://raid.wiki.kernel.org/index.php/Linux_Raid cool Tips here] }}
===Hard Drives===
A software RAID array will be automatically configured as part of the installation process for servers which contain multiple hard drives. This is to ensure redundancy, so if one disk fails the system will still function.
{{Note box|As per the release notes, SME Server 10 RAID configuration is slightly different to previous versions. See Default RAID Rationale below for more details.}}
====Identifying Hard Drives====
The specifics of the RAID setup depends on the number of drives available, to balance redundancy and capacity.
It may not always be obvious which physical hard drive maps to which logical device. The simplest method to verify this if you have a drive with S.M.A.R.T. capability is to map the serial number on the physical package with that displayed by smartctl. Assuming the device of interest is '''sda''' , (a SCSI drive), then you would issue the following command from root:
The root and swap volumes are configured using LVM on the RAID device /dev/md1 as follows:
*1 drive - no RAID
*2 drives - RAID 1
*3 drives - RAID 1 + hot spare
*4 drives - RAID 6
*5+ drives - RAID 6 + hot spare
The /boot volume and EFI partition if necessary is always a non-LVM RAID 1 array on the device /dev/md0.
If you use a hardware RAID controller to manage your drives, this should be configured to present a single volume, which SME will configure without software RAID.
<br />
===Default RAID Rationale===
The differences in RAID layout between SME Server 10 and previous versions is summarised below:
{| class="wikitable"
|+
!Number of Drives
|'''SME Server 10'''
|'''Previous Versions'''
|-
|1
|No software RAID
|Degraded RAID 1
|-
|2
| colspan="2" |Software RAID 1
|-
|3
| colspan="2" |RAID 1 + hot spare
|-
|4
|RAID 6
| rowspan="3" |RAID 5 + hot spare
|-
|5
| rowspan="3" |RAID 6 + hot spare
|-
|6
|-
|7+
|RAID 6 + hot spare
|}
The main differences are no degraded RAID 1 for a single disk install, which better supports virtualised and hardware RAID use cases, and a preference for RAID 6 over RAID 5.
This is to reduce the risk of a single disk failure bringing down the array. While consumer hard drives have got significantly larger over time, their unrecoverable read error rate (URE) has remained at 1 per 10^14 bits, or 12TB.
As an example, imagine a server with 5 x 4TB drives. Under previous versions of SME Server this would have been configured as a 4 disk RAID 5 array with 1 hot spare.
If one drive failed, the hot spare would become active and the array would begin to rebuild. This would require reading all 3 disks and, at some point during that 12TB operation, it’s very likely that an unrecoverable error would be encountered. At this point, the whole array would fail.
In comparison, a RAID 6 array is tolerant to two disk failures. While this does not entirely solve the risk of a URE during rebuild, it significantly reduces the likelihood of it taking down the array.
'''Note:''' RAID is a convenient method of protecting server availability from a drive failure. It does not remove the need for regular backups, which can be configured using the Server Manager.
===Disk Layout===
Mirroring drives in the same IDE channel (eg. hda and hdb) is not desirable. If that channel goes out, you may lose both drives. Also, performance will suffer slightly.
The preferred method is to use the primary location on each IDE channel (eg. hda and hdc). This will ensure that if you lose one channel, the other will still operate. It will also give you the best performance.
In a 2 drive setup put each drive on a different IDE channel:
IDE 1 Primary - Drive 1 <br />
IDE 1 Secondary - CDROM <br />
IDE 2 Primary - Drive 2
'''Obviously this section is obsolete with SATA hard drives because each disk has its own channel.'''
<br />
===Identifying Hard Drives===
It may not always be obvious which physical hard drive maps to which logical device.
The first step would be to be able to identify all block devices present on your server. This could be done by using two commands
lsblk
or the following
findmnt
Then, once you identified a block device , the simplest method to verify which physical drive it is, is using S.M.A.R.T. capability to map the serial number on the physical package with that displayed by smartctl. Assuming the device of interest is '''sda''', (a SCSI drive), then you would issue the following command as root:
smartctl -i /dev/sda
smartctl -i /dev/sda
Or if an IDE Drive
Or if an IDE Drive
smartctl -i /dev/hda
smartctl -i /dev/hda
<br />
===Adding Additional Drives===
For servers which were installed with 2+ drives and have a working RAID array, it is possible to add an additional drive which will become a hot spare, ready to be activated in case of drive failure.
See also [[AddExtraHardDisk]]. It's an alternative for part of the data if you have only one drive and you want to use RAID1. But better solution is to reinstall SME10 with 2 drives.
'''Ensure that any new drives are the same size or larger than your existing drives.'''
*Shut down the machine
*Install one additional drive at a time
*Boot up
*At the login prompt log on as admin with the root password to get to the admin console
*Go to #5 Manage disk redundancy
*Accept the option to add an additional drive
If the Manage disk redundancy page displays the message "The free disk count must equal one" and "Manual intervention may be required", then you probably have additional hard drives that need to be disconnected while the RAID is set up. An external USB drive will have this effect, and should be unplugged.
====Reusing Hard Drives====
====Reusing Hard Drives====
If it was ever installed on a Windows machine (or in some cases an old system) then you will need to clear the MBR first before installing it.
*MBR formatted disks
If it was ever installed on a Windows machine, or any of the *BSDs, (or in some cases an old system with RAID and/or LVM) then you will need to clear the MBR first before installing it.
From the linux command prompt, type the following:
From the linux command prompt, type the following:
#dd if=/dev/zero of=/dev/hdx bs=512 count=1
#dd if=/dev/zero of=/dev/hdx bs=512 count=1
or
#dd if=/dev/zero of=/dev/sdx bs=512 count=1
You MUST reboot so that the empty partition table gets read correctly.
You MUST reboot so that the empty partition table gets read correctly.
For more information, check: http://bugs.contribs.org/show_bug.cgi?id=2154
For more information, check: http://bugs.contribs.org/show_bug.cgi?id=2154
*For disks previously formatted as GPT this is insufficient. It's probably best to use gdisk or parted or partx to delete the partitions; there are other tools that will work. Parted has limited support for LVM.
*To remove the (hardware) RAID configuration that is stored at the end of the drive, do:
#dd if=/dev/zero of=/dev/sdx bs=512 count=2048 seek=$((`blockdev --getsz /dev/sdx` - 2048))
====Upgrading the Hard Drive Size====
====Upgrading the Hard Drive Size====
Note: these instructions are only applicable if you have a RAID system with more than one drive. They are not applicable to a single-drive RAID 1 system, and increasing the useable space on such a system by cloning the existing single drive to a larger drive is not supported. See http://bugs.contribs.org/show_bug.cgi?id=5311
Note: these instructions are only applicable if you have a RAID system with more than one drive. They are not applicable to a single-drive RAID 1 system, and increasing the useable space on such a system by cloning the existing single drive to a larger drive is not supported. See http://bugs.contribs.org/show_bug.cgi?id=5311
* CAUTION MAKE A FULL BACKUP!
*CAUTION MAKE A FULL BACKUP!
* Ensure you have e-smith-base-4.16.0-33 or newer installed. [or Update to at least 7.1.3]
*Ensure you have e-smith-base-4.16.0-33 or newer installed. [or Update to at least 7.1.3]
HD Scenario - Current 250gb drives, new larger 500gb drives
HD Scenario - Current 250gb drives, new larger 500gb drives
# Shut down and install larger drive in system to old . Unplug any USB-connected drives.
#Shut down and install one larger drive in system for one old HD. Unplug any USB-connected drives.
# Boot up and manage raid to add new (larger) drive to system.
#Boot up and login to the admin console and use option 5 to add the new (larger) drive to system.
# Wait for raid to fully sync.
#Wait for raid to fully sync.
# Repeat steps 1-3 until all drives in system are upgraded to larger capacity.
#Repeat steps 1-3 until all drives in system are upgraded to larger capacity.
# Ensure all drives have been replace with larger drives and array is in sync and redundant!
#Ensure all drives have been replace with larger drives and array is in sync and redundant!
# Issue the following commands:
#Issue the following commands:
{{Note box|SME9 uses /dev/md1 not /dev/md2.}}
mdadm --grow /dev/md2 --size=max
mdadm --grow /dev/md2 --size=max
Notes :
Notes :
====Replacing and Upgrading Hard Drive after HD fail====
*All of this can be done while the server is up and running with the exception of #1.
Note: See [[Bugzilla 6632]] these instructions are applicable if you have a faulty HD on a RAID system with more than one drive and intend to upgrade the sizes as well as replacing the failed HD. They are not applicable to a single-drive RAID 1 system, and increasing the useable space on such a system by cloning the existing single drive to a larger drive is not supported. See http://bugs.contribs.org/show_bug.cgi?id=5311
*These instructions should work for any raid level you have as long as you have >= 2 drives
*If you have disabled lvm , you don't need the pvresize or lvresize command, therefore the final line becomes
ext2online -C0 /dev/md2 <nowiki>#</nowiki>(or whatever / is mounted to)
or If you receive an "command not found" error, try this:
resize2fs /dev/md2 &
====Replacing and Upgrading a Hard Drive after HD fail====
Note: See [[Bugzilla: 6632]] and [[Bugzilla:6630]] a suggested sequence for Upgrading a Hard Drive size is detailed after issue when attempting to sync a new drive when added first as sda.
Note: These instructions are applicable if you have a faulty HD on a RAID system with more than one drive and intend to upgrade the sizes as well as replacing the failed HD. They are not applicable to a single-drive RAID 1 system, and increasing the useable space on such a system by cloning the existing single drive to a larger drive is not supported. See http://bugs.contribs.org/show_bug.cgi?id=5311
* CAUTION MAKE A FULL BACKUP!
*CAUTION MAKE A FULL BACKUP!
* Ensure you have e-smith-base-4.16.0-33 or newer installed. [or Update to at least 7.1.3]
*Ensure you have e-smith-base-4.16.0-33 or newer installed. [or Update to at least 7.1.3]
HD Scenario - Current 250gb drives, new larger 500gb drives
HD Scenario - Current 250gb drives, new larger 500gb drives
# Remove failed HDD from system, ensure remaining drive is on sda on its own and boot up.
#Remove failed HDD from system, ensure remaining drive is on sda on its own and boot up.
# Shutdown, connect one new 500gb drive as sdb and boot up
#Shutdown, connect one new 500gb drive as sdb and boot up
# Login to the admin panel and manage raid to add new (larger) drive to system.
#Login to the admin panel and manage raid to add new (larger) drive to system.
# Wait for raid to fully sync
#Wait for raid to fully sync
# Do full reboot with those 2 drives in place (1 original, 1 new)
#Do full reboot with those 2 drives in place (1 original, 1 new)
#Shutdown again, disconnect the original drive, and connect the new drive just sync'd as sda (in place of original)
#Shutdown again, disconnect the original drive, and connect the new drive just sync'd as sda (in place of original)
# Boot up again with just the one new drive in place, and confirm it boots OK.
#Boot up again with just the one new drive in place, and confirm it boots OK.
# Shutdown, and connected the other 500gb drive as sdb
#Shutdown, and connected the other 500gb drive as sdb
# Boot up login to admin panel and add sdb to the array, and wait for raid to fully sync.
#Boot up login to admin panel and add sdb to the array, and wait for raid to fully sync.
# Reboot and ensure all drives have been replaced with larger drives and array is in sync and redundant!
#Reboot and ensure all drives have been replaced with larger drives and array is in sync and redundant!
# Issue the following commands:
#Issue the following commands:
{{Note box|SME9 uses /dev/md1 not /dev/md2.}}
mdadm --grow /dev/md2 --size=max
mdadm --grow /dev/md2 --size=max
Notes :
Notes :
====Raid Notes====
*These instructions should work for any raid level you have as long as you have >= 2 drives
*If you have disabled lvm , you don't need the pvresize or lvresize command, therefore the final line becomes
If your persistent on getting a hardware raid, buy a well supported raid card which has a proper RAID BIOS. This hides the disks and presents a single disk to Linux (http://linuxmafia.com/faq/Hardware/sata.html). Please check that it is supported by the kernel and has some form of management. Also avoid anything which requires a driver. Try googling for the exact model of RAID controller before buying it. Please note that you won't get a real hardware raid controller cheap.
ext2online -C0 /dev/md2 <nowiki>#</nowiki>(or whatever / is mounted to)
or If you receive an "command not found" error, try this:
resize2fs /dev/md2 &
====RAID Notes====
Many on-board hardware raid cards are in fact software RAID. Turn it off as cheap "fakeraid" cards aren't good for Linux. You will generally get better performance and reliability with Linux Software RAID (http://linux-ata.org/faq-sata-raid.html). Linux software RAID is fast and robust.
If you are insistent on getting a hardware RAID, buy a well supported RAID card which has a proper RAID BIOS. This hides the disks and presents a single disk to Linux (http://linuxmafia.com/faq/Hardware/sata.html). Please check that it is supported by the kernel and has some form of management. Also avoid anything which requires a driver. Try googling for the exact model of RAID controller before buying it. Please note that you won't get a real hardware raid controller cheap.
It rarely happens, but sometimes when a device has finished rebuilding,
It rarely happens, but sometimes when a device has finished rebuilding,
its state doesn't change from "dirty" to "clean" until a reboot occurs.
its state doesn't change from "dirty" to "clean" until a reboot occurs.
This is cosmetic
This is cosmetic
====Periodic scrub of RAID arrays====
A Periodic scrub of RAID arrays (weekly raid check) is performed every week on Sunday at 04:22 local time, refer [[Bugzilla:3535]] and [[Bugzilla:6160]] for more information.
Theses operations are logged, however, no emails will be sent to admin as of the release of packages associated with Bug #6160 or the release of the 8.1 ISO.
====Receive periodic check of RAID by email====
There are routines in SME Server to check the RAID and sent mail to the admin user, when the RAID is degraded or when the RAID is resynchronizing. But the admin user may receive a lot of emails and sometimes messages can be forgotten.
So the purpose is to have a routine which sends email to the user of your choice each week.
nano /etc/cron.weekly/raid-status.sh
You have to change the variable '''DEST="stephane@your-domaine-name.org"''' to the email you decide to use.
#!/bin/sh
# cron.weekly/mdadm-status -- weekly status of the RAID
# 2013 Pierre-Alain Bandinelli
# distributed under the terms of the Artistic Licence 2.0
# Get status from the RAID array and send the details by email.
# Email will go to the address specified in the commandline.
set -eu
MDADM=/sbin/mdadm
[ -x $MDADM ] || exit 0 # package may be removed but not purged
'''DEST="stephane@your-domaine-name.org"'''
exec $MDADM --detail $(ls /dev/md*) | mail -s "RAID status SME Server" $DEST
save by ctrl+x
chmod +x /etc/cron.weekly/raid-status.sh
each sunday a 4h00 AM you will receive a mail which looks to this :
/dev/md1:
Version : 0.90
Creation Time : Sun Jan 6 20:50:41 2013
Raid Level : raid1
Array Size : 104320 (101.89 MiB 106.82 MB)
Used Dev Size : 104320 (101.89 MiB 106.82 MB)
Raid Devices : 2
Total Devices : 2
Preferred Minor : 1
Persistence : Superblock is persistent
Update Time : Sun Dec 22 04:22:42 2013
State : clean
Active Devices : 2
Working Devices : 2
Failed Devices : 0
Spare Devices : 0
UUID : 28745adb:d9cff1f4:fcb31dd8:ff24cb0c
Events : 0.208
Number Major Minor RaidDevice State
0 8 1 0 active sync /dev/sda1
1 8 17 1 active sync /dev/sdb1
/dev/md2:
Version : 0.90
Creation Time : Sun Jan 6 20:50:42 2013
Raid Level : raid1
Array Size : 262036096 (249.90 GiB 268.32 GB)
Used Dev Size : 262036096 (249.90 GiB 268.32 GB)
Raid Devices : 2
Total Devices : 2
Preferred Minor : 2
Persistence : Superblock is persistent
Update Time : Sun Dec 22 05:30:36 2013
State : clean
Active Devices : 2
Working Devices : 2
Failed Devices : 0
Spare Devices : 0
UUID : c343c79e:91c01009:fcde78b4:bad0b497
Events : 0.224
Number Major Minor RaidDevice State
0 8 2 0 active sync /dev/sda2
1 8 18 1 active sync /dev/sdb2
If you want to test the message sent without waiting the next sunday, you can do
/etc/cron.weekly/raid-status.sh
====nospare====
====nospare====
A system with 6 physically present harddrives thus will be formated Raid6 _not_ Raid5. Resulting capacity of course will be "n-2".
A system with 6 physically present harddrives thus will be formated Raid6 _not_ Raid5. Resulting capacity of course will be "n-2".
'''Note:''' with the release of version 7.6 and 8.0, the commandline parameter "sme nospare" has been changed to "sme spares=0" . In addition, you may also select the number of spare(s) implemented [0,1,or 2].
'''Note:''' with the release of version 7.6 and 8.0, the commandline parameter "sme nospare" has been changed to "sme spares=0" . In addition, you may also select the number of spare(s) implemented [0,1,or 2].
====remove the degraded RAID message====
When you install the smeserver with one drive with a degraded raid, you will see a 'U_' state but without warnings. If you want to leave just one 'U' in the /proc/mdstat and stop all future questions about your degraded raid state, then :
mdadm --grow /dev/md0 --force --raid-devices=1
mdadm --grow /dev/md1 --force --raid-devices=1
after that you will see this
# cat /proc/mdstat
Personalities : [raid1]
md0 : active raid1 sda1[0]
255936 blocks super 1.0 [1/1] [U]
md1 : active raid1 sda2[0]
268047168 blocks super 1.1 [1/1] [U]
bitmap: 2/2 pages [8KB], 65536KB chunk
unused devices: <none>
====Resynchronising a Failed RAID====
====Resynchronising a Failed RAID====
You can refer to 'man mdadm' or http://www.linuxmanpages.com/man8/mdadm.8.php
{{tip box|You can refer to 'man mdadm' or [http://www.linuxmanpages.com/man8/mdadm.8.php Mdadm Man page] or [[Raid:Manual_Rebuild]]}}
Sometimes a partition will be taken offline automatically. Admin will receive an email '''DegradedArray event on /dev/md2'''.
Sometimes a partition will be taken offline automatically. Admin will receive an email '''DegradedArray event on /dev/md2'''.
This will happen if, for example, a read or write error is detected in a disk in the RAID set, or a disk does not respond fast enough, causing a timeout. As a precaution, verify the health of your disks as documented in: http://wiki.contribs.org/Monitor_Disk_Health and specifically with the command:
{{note box|This will happen if, for example, a read or write error is detected in a disk in the RAID set, or a disk does not respond fast enough, causing a timeout. As a precaution, verify the health of your disks as documented in: [[Monitor_Disk_Health]] and specifically with the command:}}
smartctl -a /dev/hda
smartctl -a /dev/hda
Where hda is the device to be checked; check all of them.
Where hda is the device to be checked; check all of them.
Login as root, type console. Select Item 5. "Manage disk reduncancy"
Login as root, type console. Select Item 5. "Manage disk reduncancy"
<nowiki>--------Disk Reduncancy status as of Thursday Dec 22 -------
<nowiki>--------Disk Reduncancy status as of Thursday Dec 22 -------
Current RAID status:
Personalities : [raid1]
md2 : active raid1 hda2[0] <-- NOTICE hdb2[#] is missing. Means hdb2[#] failed.
38973568 blocks [2/1] [U_]
md1 : active raid1 hda1[0] hdb1[1]
104320 blocks [2/2] [UU]
unused devices: <none>
Only Some of the RAID devices are unclean. <-- NOTICE This message and
Manual intervention may be required.</nowiki> <-- this message.
Notice the last 2 sentences of the window above. You have some problems. <br>
Notice the last 2 sentences of the window above. You have some problems. <br>
If your system is healthy however the message you will see at the bottom of Raid Console window is:
If your system is healthy however the message you will see at the bottom of Raid Console window is:
[root@sme]# mdadm --add /dev/md2 /dev/hda2
[root@sme]# mdadm --add /dev/md2 /dev/hda2
Once you type the command the following message will appear, appropriate for your device.
[root@sme] mdadm: hot added /dev/hda2
It important to know that your devices are likely to be different, E.G your device could be /dev/sda2 or you may have more than two disks, including a hot standby. These details can always be determined from the mdstat file. Once the raid resync has been started, the progress will be noted in mdstat. You can see this real time by:
[root@sme]# watch -n .1 cat /proc/mdstat
[root@sme]# watch -n .1 cat /proc/mdstat
Also check your driver cards, since a faulty card can destroy the data on a full RAID set as easily as it can a single disk.
Also check your driver cards, since a faulty card can destroy the data on a full RAID set as easily as it can a single disk.
{{Tip box| we could use a shortcut for the raid rebuild :
mdadm -f /dev/md2 /dev/hda2 -r /dev/hda2 -a /dev/hda2}}
====Convert Software RAID1 to RAID5====
====Convert Software RAID1 to RAID5====
{{Note box|msg=these instructions are only applicable if you have SME8 and a RAID1 system with 2 hd in sync; new drive(s) must be of the same size or larger as the current drive(s)}}
{{Note box|msg=these instructions are only applicable if you have SME8 or greater and a RAID1 system with 2 hd in sync; new drive(s) must be of the same size or larger as the current drive(s)}}
{{Warning box|msg=Please make a full backup before proceeding}}
{{Warning box|msg=Please make a full backup before proceeding}}
{{Warning box|msg=Newer versions of mdadm use the v1.x superblocks stored at the beginning of the block device, which could overwrite the filesystem metadata. You’ll need to be starting with a v0.9 metadata device for the above instructions to work (which was the default for years).First, check the existing superblock version with:
{{Warning box|msg=Newer versions of mdadm use the v1.x superblocks stored at the beginning of the block device, which could overwrite the filesystem metadata. You’ll need to be starting with a v0.9 metadata device for the above instructions to work (which was the default for years).First, check the existing superblock version with:
Then, when re-creating the RAID 5 array, make sure you add the –metadata=0.9 tag so the superblock is recreated in the right place.
Then, when re-creating the RAID 5 array, make sure you add the –metadata=0.9 tag so the superblock is recreated in the right place.
Unfortunately, v1.0 give a new size for the md device (smaller than the original array), v1.1 and v1.2 corrupts the filesystem outright, so best to avoid these cases entirely. Creating a new array with v1.x superblocks when the original was v0.9 is likewise outright destructive.}}
Unfortunately, v1.0 give a new size for the md device (smaller than the original array), v1.1 and v1.2 corrupts the filesystem outright, so best to avoid these cases entirely. Creating a new array with v1.x superblocks when the original was v0.9 is likewise outright destructive.}}
<ol></li><li>Login as root
<ol><li>Login as root
</li><li>Move to /boot (we must create a new initrd image to load raid5 driver).
</li><li>Move to /boot (we must create a new initrd image to load raid5 driver).
cd /boot
cd /boot
</li><li>Now, create on the new drive(s) the correct partition table.
</li><li>Now, create on the new drive(s) the correct partition table.
sfdisk -d /dev/sda > tmp.out
sfdisk -d /dev/sda > tmp.out
sfdisk /dev/sdc < tmp.out
</li><li>Repeat the last step for each new hd (sdd, sde ecc.).
</li><li>Repeat the last step for each new hd (sdd, sde etc.).
</li><li>Create the new array
</li><li>Create the new array
mdadm --create /dev/md2 -c 256 --level=5 --raid-devices=2 /dev/sda2 /dev/sdb2
mdadm --create /dev/md2 -c 256 --level=5 --raid-devices=2 /dev/sda2 /dev/sdb2
mdadm: /dev/sda2 appears to be part of a raid array:
level=raid1 devices=2 ctime=Fri Dec 18 13:17:49 2009
mdadm: /dev/sdb2 appears to be part of a raid array:
level=raid1 devices=2 ctime=Fri Dec 18 13:17:49 2009
Continue creating array? y
mdadm: array /dev/md2 started.
</li><li>Wait for resync; monitor the status with
</li><li>Wait for resync; monitor the status with
cat /proc/mdstat
cat /proc/mdstat
root# cat /proc/mdstat
Personalities : [raid0] [raid1] [raid5]
md2 : active raid5 sdb1[2] sda1[0]
1048512 blocks level 5, 256k chunk, algorithm 2 [2/1] [U_]
[==>..................] recovery = 12.5% (132096/1048512) finish=0.8min speed=18870K/sec
</li><li>Reboot
</li><li>Reboot
exit
exit
mdadm --add /dev/md2 /dev/sdc2
mdadm --add /dev/md2 /dev/sdc2
</li><li>Repeat the last step for each new hd (sdd2, sde2 ecc.)
</li><li>Repeat the last step for each new hd (sdd2, sde2 etc.)
</li><li>Grow the array
</li><li>Grow the array
</li><li>Wait for array reshaping. This part can take a substantial amount of time; monitor it with
</li><li>Wait for array reshaping. This part can take a substantial amount of time; monitor it with
cat /proc/mdstat
cat /proc/mdstat
root# cat /proc/mdstat
Personalities : [raid0] [raid1] [raid5]
md2 : active raid5 sdc1[2] sdb1[1] sda1[0]
1048512 blocks super 0.91 level 5, 256k chunk, algorithm 2 [3/3] [UUU]
[==>..................] reshape = 12.5% (131520/1048512) finish=2.5min speed=5978K/sec
</li><li>Issue the following commands:
</li><li>Issue the following commands:
pvresize /dev/md2
pvresize /dev/md2
lvresize -l +100%FREE main/root
resize2fs /dev/main/root
</li></ol>
</li></ol>
Notes :
Notes :
*If you have disabled lvm
#you don't need the pvresize or lvresize command
#the final line becomes resize2fs /dev/md2 (or whatever / is mounted to)
#More info: http://www.arkf.net/blog/?p=47
== Add another Raid to mount to /home/e-smith/files ==
this is inspired from previous content of [[AddExtraHardDisk]] and particularly the part [[AddExtraHardDisk#Additional steps to create a raid array from multiple disks]] but updated to 2022 and SME10
1 you need to check what disk you want, using lsblk<syntaxhighlight lang="bash">
# lsblk --fs
NAME FSTYPE LABEL UUID MOUNTPOINT
sda
├─sda1 vfat B93A-85A4 /boot/efi
├─sda2 xfs 89e9cc9e-d3d2-4d02-bad5-2698aea0a510 /boot
├─sda3 swap 64d21f89-4d7c-417a-907e-34236f6cd0be [SWAP]
└─sda4 xfs 65bf712c-2186-4524-aae8-edd8151de1e7 /
sdb
sdc
</syntaxhighlight>then you can create the Raid array. We assume you only need onethen you need to rebuild the grub.conf, depending on your system is EFI or legacy use the appropriate command#EFI
grub2-mkconfig -o /boot/efi/EFI/centos/grub.cfg
<nowiki>#</nowiki>Legacy
grub2-mkconfig -o /boot/grub2/grub.cfg
Raid partition, and hence do not need to partition it.<syntaxhighlight lang="bash">
#create array
mdadm --create --verbose /dev/md11 --level=1 --raid-devices=2 /dev/sdb /dev/sdc
# add to mdadm.conf
mdadm --detail --scan --verbose /dev/md11 >> /etc/mdadm.conf
</syntaxhighlight>then format it and enable quotas. If you want to add a LVM Layer, this is just before that !<syntaxhighlight lang="bash">
mkfs.xfs /dev/md11
</syntaxhighlight>now you have<syntaxhighlight lang="bash">
# lsblk --fs
NAME FSTYPE LABEL UUID MOUNTPOINT
sda
├─sda1 vfat B93A-85A4 /boot/efi
├─sda2 xfs 89e9cc9e-d3d2-4d02-bad5-2698aea0a510 /boot
├─sda3 swap 64d21f89-4d7c-417a-907e-34236f6cd0be [SWAP]
└─sda4 xfs 65bf712c-2186-4524-aae8-edd8151de1e7 /
sdb linux_raid_member localhost.localdomain:11 6c4b9640-7349-15fe-28b1-78843d9a149a
└─md11 xfs 0ab4fe2a-aa81-4728-90d8-2f96d4624af8
sdc linux_raid_member localhost.localdomain:11 6c4b9640-7349-15fe-28b1-78843d9a149a
└─md11 xfs 0ab4fe2a-aa81-4728-90d8-2f96d4624af8
</syntaxhighlight>then you need to mount it temporary to move your content<syntaxhighlight lang="bash">
mkdir /mnt/newdisk
mount /dev/md11 /mnt/newdisk
rsync -arv /home/e-smith/files/ /mnt/newdisk
</syntaxhighlight>When happy with result simply add an entry to you fstab, according to last lsblk output in this case you should add <syntaxhighlight lang="bash">
UUID=0ab4fe2a-aa81-4728-90d8-2f96d4624af8 /home/e-smith/files xfs uquota,gquota 0 0
</syntaxhighlight>To have the disk mounted on reboot, you need to alter grub<syntaxhighlight lang="bash">
vim /etc/default/grub
</syntaxhighlight>and alter the command line to add either "rd.md=1 rd.md.conf=1 rd.auto=1" or specifically add the uuid to mount (obviously if you add a LVM layer you will rather need to add something like rd.lvm.lv=mylvm/video rd.lvm.lv=mylvm/files)<syntaxhighlight lang="bash" line="1">
GRUB_TIMEOUT=5
GRUB_DISTRIBUTOR="$(sed 's, release .*$,,g' /etc/system-release)"
GRUB_DEFAULT=saved
GRUB_DISABLE_SUBMENU=true
GRUB_TERMINAL_OUTPUT="gfxterm"
GRUB_CMDLINE_LINUX="rhgb quiet rootflags=uquota,pquota rd.md=1 rd.md.conf=1 rd.auto=1"
GRUB_DISABLE_RECOVERY="false"
GRUB_BACKGROUND="/boot/grub2/smeserver10.png"
GRUB_GFXMODE="1024x768"
GRUB_THEME="/boot/grub2/themes/koozali/theme.txt"
</syntaxhighlight>then you need to make sure dracut will add the drivers<syntaxhighlight lang="bash">
vim /etc/dracut.conf
</syntaxhighlight>and alter the line needed (you probably will need to uncomment this line and add mdraid between the quote)<syntaxhighlight lang="bash" line="1" start="19">
# dracut modules to add to the default
add_dracutmodules+="lvm mdraid"
# install local /etc/mdadm.conf
mdadmconf="yes"
# install local /etc/lvm/lvm.conf
lvmconf="yes"
</syntaxhighlight>Finally rebuild the initfs<syntaxhighlight lang="bash">
cp /boot/initramfs-$(uname -r).img /boot/initramfs-$(uname -r).img.old
dracut --add="lvm mdraid" /boot/initramfs-$(uname -r).img $(uname -r) --force
</syntaxhighlight>
== Copy data from one disk of an old Raid mirror disk ==
Let's say you want to copy the huge amount of data you excluded from the backup to migrate from SME9 to SME10 and now you want to copy this to your new server.
This How-To assume your current install is without LVM. An extra trick is needed if you have a LVM and previous SME9 also. You simply need to rename the vg group either of the old SME or new one using a rescue disk or another Linux distro, see [[UpgradeDisk#Moving from SME 8.x to SME 9.x]].
# put one of the old drives in the server or in an external case and connect it
# use lsblk to identify the drive
# adapt the following commands
<syntaxhighlight lang="bash">
# lsblk
sdd 8:48 0 931,5G 0 disk
├─sdd1 8:49 0 250M 0 part
└─sdd2 8:50 0 931,3G 0 part
</syntaxhighlight>We assume that sd1 was the boot partition and the stuff we want is in sdd2<syntaxhighlight lang="bash">
#assemble and run on degraded
mdadm -A /dev/md126 /dev/sdd2 --run
</syntaxhighlight>now let's try to mount, it will work only if you had no LVM, or it will return this<syntaxhighlight lang="bash">
# mkdir /mnt/olddisk/
# mount /dev/md126 /mnt/olddisk/
mount: filesystem « LVM2_member » unknown
</syntaxhighlight>you can skip this step if you did not got the LVM error. Then we need to activate the LVM, and we can assume you might need also to install lvm stuffs...<syntaxhighlight lang="bash">
# yum install lvm2 -y
vgchange -a y main
mount /dev/mapper/main-root /mnt/olddisk/
</syntaxhighlight>It is now time to copy your stuffs.<syntaxhighlight lang="bash">
rsync -arvHAX /mnt/olddisk/home/e-smith/files/ /home/e-smith/files
</syntaxhighlight>then to remove safely your disk<syntaxhighlight lang="bash">
umount /dev/mapper/main-root
vgchange -a n main
mdadm --stop /dev/md126
</syntaxhighlight>
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<noinclude>[[Category:Howto]][[Category:Administration:Storage]]</noinclude>
<noinclude>
[[Category:Howto]]
[[Category:Administration:Storage]]
</noinclude>