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diff --git a/docs/operation/raid.rst b/docs/operation/raid.rst new file mode 100644 index 00000000..90483e74 --- /dev/null +++ b/docs/operation/raid.rst @@ -0,0 +1,312 @@ +.. _raid: + +###### +RAID-1 +###### + +A Redundant Array of Independent Disks (RAID) uses two or more hard disk drives +to improve disk speed, store more data, and/or provide fault tolerance. +There are several storage schemes possible in a RAID array, each offering a +different combination of storage, reliability, and/or performance. +The VyOS system supports a “RAID 1” deployment. RAID 1 allows two or more +disks to mirror one another to provide system fault tolerance. In a RAID 1 +solution, every sector of one disk is duplicated onto every sector of all +disks in the array. Provided even one disk in the RAID 1 set is operational, +the system continues to run, even through disk replacement (provided that the +hardware supports in-service replacement of drives). +RAID 1 can be implemented using special hardware or it can be implemented in +software. The VyOS system supports software RAID 1 on two disks. +The VyOS implementation of RAID 1 allows the following: + +* Detection and reporting of disk failure +* The ability to maintain system operation with one failed disk +* The ability to boot the system with one failed disk +* The ability to replace a failed disk and initiate re-mirroring +* The ability to monitor the status of remirroring + +.. _raid_instalation: + +Installation Implications +========================= + +The VyOS systems installation utility provides several options for installing +to a RAID 1 set. You can: + +* Use the install system to create the RAID 1 set +* Use the underlying Linux commands to create a RAID 1 set before running the + install system command. +* Use a previously-created RAID 1 set. + +.. note:: Before a permanent installation, VyOS runs a live installation + +Configuration +============= + +Non–RAID 1 System +----------------- + +When the VyOS system is installed, it automatically detects the presence of two +disks not currently part of a RAID array. In these cases, the VyOS +installation utility automatically offers you the option of configuring RAID 1 +mirroring for the drives, with the following prompt. + +.. code-block:: none + + Would you like to configure RAID 1 mirroring on them? + +* If you do not want to configure RAID 1 mirroring, enter “No” at the prompt + and continue with installation in the normal way. + +Non–RAID 1 to RAID 1 +-------------------- + +If you reinstall a non-RAID VyOS system on a system with two identical disks +that are not currently part of a RAID 1 set, the VyOS installation utility +automatically offers you the option of configuring RAID 1 mirroring for the +drives, with the following prompt. + +.. code-block:: none + + Would you like to configure RAID 1 mirroring on them? + +1 - To create a new RAID 1 array, enter “Yes” at the prompt. If the system +detects a filesystem on the partitions being used for RAID 1 it will prompt you +to indicate whether you want to continue creating the RAID 1 array. + +.. code-block:: none + + Continue creating array? + +2 - To overwrite the old filesystem, enter “Yes”. + +3 - The system informs you that all data on both drives will be erased. You are +prompted to confirm that you want to continue + +.. code-block:: none + + Are you sure you want to do this? + +4 - Enter “Yes” at the prompt to retain the current VyOS configuration once +installation is complete. Enter “No” to delete the current VyOS +configuration. + +5 - Continue with installation in the normal way. + + +RAID 1 to Non–RAID 1 +-------------------- + +If you reinstall VyOS software on a system with a RAID 1 set already configured, +the installation utility will detect the array and will display the following +prompt: + +.. code-block:: none + + Would you like to use this one? + +1 - To break apart the current RAID 1 set, enter “No” at the prompt. The + +installation utility detects that there are two identical disks and offers you +the option of configuring RAID 1 mirroring on them, displaying the following +prompt: + +.. code-block:: none + + Would you like to configure RAID 1 mirroring on them? + +2 - To decline to set up a new RAID 1 configuration on the disks, enter “No” +at the prompt. The system prompts you to indicate which partition you would +like the system installed on. + +.. code-block:: none + + Which partition should I install the root on? [sda1]: + +3 - Enter the partition where you would like the system installed. The system +then prompts you to indicate whether you want to save the old configuration +data. This represents the current VyOS configuration. + +.. code-block:: none + + Would you like me to save the data on it before I delete it? + +4 - Enter “Yes” at the prompt to retain the current VyOS configuration once +installation is complete. Enter “No” to delete the current VyOS configuration. + +5 - Continue with installation in the normal way. + +RAID 1 to RAID 1 +---------------- + +If you reinstall the VyOS software on a system with a RAID 1 set already +configured, the installation utility will detect the array and will display +the following prompt: + +.. code-block:: none + + Would you like to use this one? + +1 - To continue to use the existing RAID 1 array, enter “Yes” at the prompt. +The system prompts you to indicate whether you want to save the old +configuration data. This represents the current VyOS configuration. + +.. code-block:: none + + Would you like me to save the data on it before I delete it? + +2 - Enter “Yes” at the prompt to retain the current VyOS configuration once +installation is complete. Enter “No” to delete all current VyOS configuration. + +3 - Continue with installation in the normal way. + +RAID 1 to new RAID 1 +-------------------- + +You can also recreate the RAID 1 array on disk drives already configured for +RAID-1.The installation utility will detect the array and will display the +following prompt: + +.. code-block:: none + + Would you like to use this one? + +1 - To stop using the existing RAID 1 array, enter “No” at the prompt. +The system detects the two disks and prompts you to indicate whether you +want to configure RAID 1 mirroring in them. + +.. code-block:: none + + Would you like to configure RAID 1 mirroring on them? + +2 - To create a new RAID 1 array, enter “Yes” at the prompt. If the system +detects a file system on the partitions being used for RAID 1 it will prompt +you to indicate whether you want to continue creating the RAID 1 array. + +.. code-block:: none + + Continue creating array? + +3 - To overwrite the old filesystem, enter “Yes”. + +4 - Continue with installation in the normal way. + +Detecting and Replacing a Failed RAID 1 Disk +-------------------------------------------- + +The VyOS system automatically detects a disk failure within a RAID 1 set and +reports it to the system console. You can verify the failure by issuing the +show raid command. + +To replace a bad disk within a RAID 1 set, perform the following steps: + +1 - Remove the failed disk from the RAID 1 set by issuing the following +command: + +.. code-block:: none + + vyos@vyos:~$ remove raid RAID‐1‐device member disk‐partition + +where RAID-1-device is the name of the RAID 1 device (for example, md0) and +disk-partition is the name of the failed disk partition (for example, sdb2). + +2- Physically remove the failed disk from the system. If the drives are not +hot-swappable, then you must shut down the system before removing the disk. + +3 - Replace the failed drive with a drive of the same size or larger. + +4 - Format the new disk for RAID 1 by issuing the following command: + +.. code-block:: none + + vyos@vyos:~$ format <disk‐device1> like <disk‐device2> + +where disk-device1 is the replacement disk (for example, sdb) and disk-device2 +is the existing healthy disk (for example, sda). + +5-Add the replacement disk to the RAID 1 set by issuing the following command: + +.. code-block:: none + + vyos@vyos:~$ add raid <RAID‐1‐device> member <disk‐partition> + +where RAID-1-device is the name of the RAID 1 device (for example, md0) and +disk-partition is the name of the replacement disk partition +(for example, sdb2). + +Operation +========= + +Use this command to add a member disk partition to the RAID 1 set. Adding a +disk partition to a RAID 1 set initiates mirror synchronization, where all data +on the existing member partition is copied to the new partition. +Before adding a brand new drive to a RAID 1 set, the drive must be formatted +using + +.. code-block:: none + + vyos@vyos:~$ add raid <RAID‐1‐device> member <disk‐partition> + +Use this command to format a disk to be partitioned exactly like a second disk. +The disk to be formatted must be inactive; that is, it must not have any +partitions mounted and it must not already be part of an active RAID 1 set. +In formatting, no data is copied to the formatted device, but any existing data +on the formatted device is lost. +This command is typically used to prepare a disk to be added to a preexisting +RAID 1 set (of which disk-device2 is already a member). + +.. code-block:: none + + vyos@vyos:~$ format <disk‐device1> like <disk‐device2> + + +Displaying information about a RAID 1 set with two members ‐ one being +resynchronized. + +.. opcmd:: show raid <RAID‐1‐device> + + shows output for show raid md0 as sdb1 is being added to the RAID 1 + set and is in the process of being resynchronized. + + .. code-block:: none + + vyos@vyos:~$ show raid md0 + /dev/md0: + Version : 00.90 + Creation Time : Wed Oct 29 09:19:09 2008 + Raid Level : raid1 + Array Size : 1044800 (1020.48 MiB 1069.88 MB) + Used Dev Size : 1044800 (1020.48 MiB 1069.88 MB) + Raid Devices : 2 + Total Devices : 2 + Preferred Minor : 0 + Persistence : Superblock is persistent + Update Time : Wed Oct 29 19:34:23 2008 + State : active, degraded, recovering + Active Devices : 1 + Working Devices : 2 + Failed Devices : 0 + Spare Devices : 1 + Rebuild Status : 17% complete + UUID : 981abd77:9f8c8dd8:fdbf4de4:3436c70f + Events : 0.103 + Number Major Minor RaidDevice State + 0 8 1 0 active sync /dev/sda1 + 2 8 17 1 spare rebuilding /dev/sdb1 + +.. opcmd:: show raid <RAID‐1‐device> + + Use this command to display the formatting of a hard disk. + + .. code-block:: none + + vyos@vyos:~$ show disk sda format + Disk /dev/sda: 1073 MB, 1073741824 bytes + 85 heads, 9 sectors/track, 2741 cylinders + Units = cylinders of 765 * 512 = 391680 bytes + Disk identifier: 0x000b7179 + Device Boot Start End Blocks Id System + /dev/sda1 6 2737 1044922+ fd Linux raid autodetect + + + +
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