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documentation:setup_and_user_guide:software_raid_configuration_management

Software RAID

If your hardware has enough ram to use ZFS, then you should be using ZFS, and not any other form of software or hardware RAID. Software and hardware RAID DO NOT provide the kind of robust data protection that ZFS redundancy and checksums provide. ZFS checksums are done at the block level and can detect and repair bitrot transparently. Software and hardware RAID DO NOT provide these block-level protections. Software and hardware RAID will ignorantly pass corrupted data to the system AND there is no mechanism for the system to respond with, “This data is corrupt. Please consult some other part of the RAID.”

You can use software or hardware RAID if you want. But, you have been warned.

XigmaNAS supports Software JBOD, RAID 0, 1 and 5 configurations as well as Hardware RAID. This section describes configuring Software RAID 5. The process is virtually identical for all the others with the exception of using geom. Vinum (unstable).

Here is the FreeBSD module name and equivalent:

  • JBOD: Geom concat
  • RAID 0: Geom stripe
  • RAID 1: Geom mirror
  • RAID 5: Geom RAID5 (Thanks to Arne for developing this non-official FreeBSD module!!)

All disks must be the same size for all RAID types with the exception of JBOD and Geom RAID5 (it will be based on the smallest disk).

Important - RAID does not equal backup. Even if you create a RAID array you must still keep another copy of your data in a different location.

The XigmaNAS team recommends configuring each of the RAID Disks as standalone Storage Disks first to ensure they are fully functional and supported under XigmaNAS. Once confirmed, remove any of the mount points and Disks for the RAID drives to ensure a clean start. The following description assumes that the drives have been confirmed as functional.

The High-Level process flow for configuring a simple RAID array is:

  1. Add Disks
  2. Format Disks for “Software RAID”
  3. Create the RAID array using the previously formatted for “Software RAID”
  4. Format the newly created RAID array in UFS filesystem
  5. Add Mount Point
  6. Enable Services (CIFS, FTP, etc.)
  7. For CIFS you have to create share.
To remove a RAID array, remove the mount point first and delete the RAID.

Add the Disks

Follow the Add Disk process as described above to add each of the Disks to be used in a RAID array. In the example below, I have added 4 identically sized hard drives.

Ensure the drives are in an ONLINE status.

You cannot use the 2nd partition of a XigmaNAS boot drive as a part of a RAID array. Only whole disks can be used to form a RAID array.

Prepare (format) the disks

Open the Disk:Format TAB, select each of the Disks in turn and ensure the File system is changed to Software RAID, click the Format Disk button and confirm your action.

Repeat for all Disks to be used in the RAID array.

The result should be for example:

Erasing MBR and all partitions:
Creating one partition:
******* Working on device /dev/ad1 *******
Initializing partition:
Destroying old GMIRROR information:
Done!

Create the Software RAID array

Open the Disks/Software RAID page and choose your Software RAID type.

For our example, we select ‘Geom RAID5’:

Click the icon on the right-hand side to Add a new RAID 5.

Enter a RAID name for the RAID.

Click and select each of the drives to be used in this RAID array.

Drives will not appear here unless they have previously been formatted as Software RAID

Click the Add button and when prompted, click the Apply Changes button.

Creating a RAID 5 array can take a long time:

But you can use your raid during the building process! (even if it’s in ‘REBUILDING state).

The status field will not immediately update.

Format the software RAID array

When the Status is up or rebuilding, then the RAID array must be formatted.

Open the Disk:Format menu and choose the newly created RAID array:

Leave the Type as UFS (GPT and Soft Update), click the Format Disk button and confirm.

A display similar to this should be output (example when the RAID 5 was in state ‘rebuilding’):

(You should have lot’s of more line as this example! On this example the drive was a small 200MB)

Create the mount point

Once the RAID array is formatted, all that is left is to mount the array. Open the Disk/Mount Point page and click the wiki:documentation_setup_and_user_guide_basic.add.png icon on the right-hand side.

From the Disk drop-down, select the RAID disk. The RAID name you previously configured is visible.

Change the Partition to EFI – GPT

Enter a useful Share name and click the Add button.

The Status should display as configuring, and then click the Apply Changes button and the Status should update to UP.

Your Geom RAID5 array is now ready for use. If you have already enabled CIFS, FTP or NFS, then the array, with the defined Share name, will be visible across your network.

Software RAID array status

You can verify the status of your RAID array from:

  • Status/Disks page and select the Information Tab
  • Disks/Software RAID/geom used page and select the Information Tab.

A healthy RAID array will show all the State: values as UP or COMPLETE.

RAID 1 and RAID 5 arrays may take some time to synchronize completely, be patient and monitor the status of the RAID synchronization by continuing to refresh the Information page.

Replacing a failed hard drive on a gmirror array

Note - Supplemental step by step instructions for removing / replacing failed drives in SoftRAID1 and SoftRAID 5 arrays are available in FAQs:

In the case of a failure on one hard drive, your RAID array is in the ‘DEGRADED’ state:

Here is an example with the RAID 1 array named “mirroire” in “DEGRADED” state with a missing hard drive:

And we can check that the disk is missing in the Disk/Management page:

We can see that in our example, the disk da1 is missing.

First Step

For replacing this disk: Stop XigmaNAS and replace this disk with a new one (in the same place on the ATA or SCSI channel). And restart XigmaNAS.

After restarting XigmaNAS, the Disk/Management should display it back (ONLINE if it’s the same, or CHANGED if it’s a different disk).

The Software RAID 1 status is still ‘DEGRADED’, we must add this new disk:

Second Step

Open the Disk/Software RAID/Geom mirror/Tools page and select your DEGRADED RAID array and action “forget” (The Disk field is not used on this first action).

Third Step

Still on this Disk/Software RAID/Geom mirror/Tools page, re-select your DEGRADED RAID array, the select the newly replaced Disk, and choose action “insert”:

You can now check your RAID status (Disk/Software RAID/Geom mirror): It should be ‘REBUILDING” or “COMPLETE” (the time needed for rebuilding depend of your disk size).

You should check the Disk/Mount Status too, as sometimes needs a remount.

Replacing a failed hard drive on a graid5 array

In the case of a failure on one hard drive, your RAID array is in the ‘DEGRADED’ state.

Here is an example with the RAID 5 array “bigdisk” with a missing hard drive:

And the disk is missing:

First Step

For replacing this disk: Stop XigmaNAS and replace this disk with a new one (in the same place on the ATA or SCSI channel). And restart XigmaNAS.

After restarting XigmaNAS, the Disk/Management should display it back (ONLINE if it’s the same, or CHANGED if it’s a different disk).

The Software RAID 5 status is still ‘DEGRADED’, we must add this new disk:

Second Step

Open the Disk/Software RAID/Geom Raid5/Tools page and select your DEGRADED RAID array, the replaced Disk name and action “insert”.

You can now check your RAID status (Disk/Software RAID/Geom raid5): It should be ‘REBUILDING” or “COMPLETE” (the time needed for rebuilding depends on your disk size).

You should check the Disk/Mount Status too, as sometimes needs a remount.

Software RAID configuration with geom vinum

Geom Vinum is all in one module permits you to create a software RAID 0,1 and 5 arrays. But, for the moment the XigmaNAS team doesn’t recommend you to use it because too many users have met with problems using the RAID 5 option of this tool.

Complex Software RAID combinations (RAID 1+0, 5+0, etc..)

XigmaNAS permits you to create advanced Software RAID combinations, for example:

  • RAID 1+0: Permits you to create a RAID 0 array using RAID 1 arrays
  • RAID 5+0: Permits you to create a RAID 0 array using RAID 5 arrays
  • RAID X + Y: Permits you to create a RAID Y array using RAID X arrays

The High-Level process flow for configuring a complex RAID X + Y array is:

  1. Add the Disks (4 disks minimum for a RAID 1+0, 6 disks for a RAID 5+0)
  2. Format Disks for “Software RAID”
  3. Create the RAID X arrays using the previously formatted for “Software RAID”
  4. Format the newly created RAID X arrays for “Software RAID”
  5. Create the RAID Y array using the previously RAID X arrays formatted for “Software RAID”
  6. Add Mount Point
  7. Enable Services (CIFS, FTP, etc.)
documentation/setup_and_user_guide/software_raid_configuration_management.txt · Last modified: 2018/07/08 21:12 by dw5304