OviOS Linux - The Admin Guide

The OviOS Linux Admin Guide

OviOS Linux is a linux based storage OS, with out-of-the-box support for iSCSI, SMB and NFS.

The ovios-shell is the storage management shell for OviOS Linux. The ovios-shell is designed to assist in setting up the server, and requires very little Linux/UNIX/storage knowledge. Most commands are interactive and if an error occurs, the messages can be found using 'ovilogs', or manually reading the sys.log file.

You should not create pools, volumes, LUNs and targets using the Linux bash shell. These will not work well in ovios-shell. Objects created and managed with the ovios-shell have specific configurations and specific options set.

The ovios_restore command can assist in setting the ovios specific options to pools not created with the ovios-shell.

There are 4 main steps to create a storage server using the ovios-shell, and 2 additional steps for replication and DR.

1. Configure the network

There are 3 main issues when configuring the network. IPs, aggregated links, and DNS. OviOS provides two tools for the network:

'bondadm' to create aggregated links, and 'netsetup' , to set up the network interfaces.

OviOS does not provide an automated method to configure the DNS.

Edit the resolv.conf file manually if the DNS must be configured.

1.1. bondadm

The syntax is:

bondadm -n name -i interface1 -i interface2 -m mode

You can use 'bondadm' from the ovios-shell, or from the linux shell. (Type 'linuxcmd' to drop to the linuxCLI)

If used from the ovios-shell, bondadm opens it's own CLI menu. It requires only the arguments.

For example, creating a new bonded interface called bond0, using physical interfaces eth0, eth1 and eth2, and mode 0.

ovios-shell> bondadm

Type only the command arguments, like: -l | -h | -n etc.

To exit the bondadm CLI enter q or quit.

bondadm > -h

    The command bondsetup creates a bonded interface using one

    or more physical interfaces.

    Syntax: bondadm -[l|n|m|i|r|h|v]

    OPTIONS:

            -l : lists all bonded interfaces and their physical interfaces

            -n : name of the interface to be created.

            -m : aggergation mode of the new bond.

            Possible options are: 0 1 2 3 4 5 6

                            0 = balance-rr (default)

                            1 = active-backup

                            2 = balance-xor

                            3 = broadcast

                            4 = 802.3ad

                            5 = balance-tlb

                            6 = balance-alb

            -i : physical interfaces to bond. If more than one, enter

                     -i multiple times. Ex: -i eth0 -i eth2

            -r : removes a bonded interface. Requires bond name.

            -h : print usage

            -v : print version

Type only the command arguments, like: -l | -h | -n etc.

To exit the bondadm CLI enter q or quit.

bondadm > q

ovios-shell>

Where: eth0, eth1 and eth2 are physical interfaces.

bond0 is the name given to the new aggregated link

0 is the mode chosen.

See more here.

1.2. netsetup

Type netsetup in ovios-shell or the linux shell.

ovios-shell> netsetup

OviOS Linux netsetup utility

Select an interface to configure

Interface : eth0

Enter interface name to configure: eth0

Selected interface: eth0

Select a service:

1. DHCP

2. Static IP

Enter 1 or 2: 1

Selected dhcp service.

If you choose DHCP, you can also setup MTU size (Jumbo Frames), after which netsetup will configure the interface and run dhcp to acquire an IP.

If you choose static service, the tool will ask for an IP, and the following optional values: Gateway, broadcast, subnet, MTU size, Speed and duplex settings, after which it will configure the interface and enable it.

2. Create RAID sets / storage pools

There are multiple options available:

1. Add Raid0 (Stripped devices.) pool

2. Add Raid1 (Mirrored devices. mirror) pool

3. Add Raid5 (raidz) pool

4. Add Raid6 (raidz2) pool

5. Add Raid10 (mirrored stripped) pool

2.1. Create Pools

Type 'storage' to find available drives:

The command storage can display devices by-id, by-path, all or simple

ovios-shell> storage -h

===========================================================

=        Your root disk is /dev/sda2

=        your boot partition is /dev/sda1

=        Do not use /dev/sda2 to create pools

=        It will destroy your OviOS installation

===========================================================

===========================================================

=        Use either Path, ID or Dev names to create Pools

===========================================================

storage <option>

Where option is one of the follwing: simple, all, by-id or by-path

ovios-shell> storage by-path

===========================================================

=        Your root disk is /dev/sda2  and

=        your boot partition is

=        Do not use /dev/sda2  to create pools

=        It will destroy your OviOS installation

===========================================================

===========================================================

=        Use either Path, ID or Dev names to create Pools

===========================================================

+------------+---------------------------------------------------+--------------+-------------+

|  Dev Name  |                      By PATH                      |     Size     |   Size H    |

+------------+---------------------------------------------------+--------------+-------------+

|/dev/sr0    |                       None                        |  503517184   |  480.19 MB  |

+------------+---------------------------------------------------+--------------+-------------+

|/dev/sdc    |  /dev/disk/by-path/pci-0000:00:10.0-scsi-0:0:1:0  |  8589934592  |   8.0 GB    |

+------------+---------------------------------------------------+--------------+-------------+

|/dev/sdb    |                       None                        |  8589934592  |   8.0 GB    |

+------------+---------------------------------------------------+--------------+-------------+

|/dev/sda    |  /dev/disk/by-path/pci-0000:00:10.0-scsi-0:0:0:0  |  8589934592  |   8.0 GB    |

+------------+---------------------------------------------------+--------------+-------------+

ovios-shell>

ovios-shell> storage simple

===========================================================

=        Your root disk is /dev/sda2  and

=        your boot partition is

=        Do not use /dev/sda2  to create pools

=        It will destroy your OviOS installation

===========================================================

===========================================================

=        Use either Path, ID or Dev names to create Pools

===========================================================

+------------+--------------+-------------+

|  Dev Name  |     Size     |   Size H    |

+------------+--------------+-------------+

|/dev/sr0    |  503517184   |  480.19 MB  |

+------------+--------------+-------------+

|/dev/sdc    |  8589934592  |   8.0 GB    |

+------------+--------------+-------------+

|/dev/sdb    |  8589934592  |   8.0 GB    |

+------------+--------------+-------------+

|/dev/sda    |  8589934592  |   8.0 GB    |

+------------+--------------+-------------+

ovios-shell>

Type 'pool create' to create a storage pool.

ovios-shell> pool create

====================================================================================

= Create a storage pool for volumes and LUNs

= Do not use /dev/sda2

/dev/sdb2  as it will wipe your OviOS installation

= Make sure you don't use disks which are part of exported pools either

====================================================================================

1. Add Raid0 (Stripped devices.) pool

2. Add Raid1 (Mirrored devices. mirror) pool

3. Add Raid5 (raidz) pool

4. Add Raid6 (raidz2) pool

5. Add Raid10 (mirrored stripped) pool

Choose a raid level for the new pool (Default: 1):

Enter the name for the new pool: OVIOSPOOL

Enter devices to add to the pool: /dev/disk/by-id/wwn-0x15272361820407353344x

Created pool OVIOSPOOL successfully

Enable compression? (Default: yes) [ y|n ]

Enabling compression on OVIOSPOOL

You can list all storage pools using the 'pool list' command

ovios-shell>

In this example a storage pool of RAID level 0, called OVIOSPOOL was created using the device '/dev/disk/by-id/wwn-0x15272361820407353344x'

ovios-shell accepts devices which can be found in /dev/, such as sda, sdc, sdd etc. , or use the full path, such as /dev/disk/by-path/disk1 etc

For simplicity, the admin should use only dev names (sdb sdc etc).

When the pools are imported during a boot up, the zfs-admin script will import the devices by path.

2.2. Assign spares and log devices

During pool creation, the admin can specify spare and log devices at the end of the disk list, for EX:

Enter devices to add to the pool: sdb sdc sdd spare sde sdf log sdm

In a mirrored pool (Raid10) you can add spares at the end of the last mirror created, or at the end of each mirror.

Enter devices to add to the pool: sdb sdc log sdd spare sde

Enter devices to create the mirror: sdf sdg spare sdh log sdi

The better method is to use 'pool modify' to add/ remove spares and logs.

For example add a spare device to a pool:

ovios-shell> pool modify

        =====================================

        1. Add spare device(s)

        -------------------------------------

        2. Add read cache device(s)

        -------------------------------------

        3. Add write cache (log) device(s)

        -------------------------------------

        4. Remove spare device(s)

        -------------------------------------

        5. Remove read cache device(s)

        -------------------------------------

        6. Remove write cache (log) device(s)

        -------------------------------------

        q. Exit this menu

        =====================================

Enter your choice: 1

Enter pool to modify: OVIOSPOOL

Enter device(s) to add as spare(s): /dev/disk/by-path/pci-0000:00:10.0-scsi-0:0:1:0

Success: adding spare device(s) ==> Pool: OVIOSPOOL ==> Dev: /dev/disk/by-path/pci-0000:00:10.0-scsi-0:0:1:0

Press ENTER to continue...

        =====================================

        1. Add spare device(s)

        -------------------------------------

        2. Add read cache device(s)

        -------------------------------------

        3. Add write cache (log) device(s)

        -------------------------------------

        4. Remove spare device(s)

        -------------------------------------

        5. Remove read cache device(s)

        -------------------------------------

        6. Remove write cache (log) device(s)

        -------------------------------------

        q. Exit this menu

        =====================================

Enter your choice: q

ovios-shell>

3. Set up SAN (iSCSI)

OviOS can be used as an iSCSI server to easily provide block storage devices to iSCSI initiators. OviOS LUNs can be used in UNIX/Linux environments, Windows or VMWare.

To setup an iSCSI server, the admin must follow 3 simple steps:

1. create iSCSI targets.

2. create LUNs.

3. map the LUNs to targets.

Start the iSCSI server with 'iscsi start'

ovios-shell> iscsi start

     Starting the iSCSI Target Server...

  *                                                             [  OK  ]

     Configuring targets...

  *                                                             [  OK  ]

ovios-shell>

Enable the server to start automatically during boot:

ovios-shell> options iscsi.enable 1

Changing option: iscsi.enable ==> on

ovios-shell>

Type 'options iscsi' for all iscsi related options.

ovios-shell> options iscsi

option iscsi.debug off

option iscsi.port

option iscsi.enable "on"

option iscsi.address

ovios-shell>

By default, the iSCSI port is 3260, and all IP addresses are enabled.

3.1. Create iSCSI targets

Run 'target create' and enter a name for the target when prompted to do so.

Enter only a name for the target, the IQN and server identifier will be added automatically by the ovios-shell.

ovios-shell> target create

==================================================================================

= This command creates an iSCSI target. You can create multiple targets

= and control what initiators can connect to them.

= You can map LUNs to specific targets, thus controlling

= which client has access to each LUN.

==================================================================================

The IQN will be appended by the OS. Enter a custom target name: ovios-tg01

Target added successfully

If no innitiator IP or IQN is assigned to this target, all initiators will have access and will be able to connect.

Would you like to define an initiator that can access this target? (Default: no) [y|n] y

Enter IP or IQN of the initiator to access this target: 192.168.0.106

Add another initiator? (Default: no) [y | n]: y

Enter IP or IQN: 192.168.0.107

Add another initiator? (Default: no) [y | n]: y

Enter IP or IQN:  iqn.2012-04.org.ovios:9bfhvndth004-tg01

Add another initiator? (Default: no) [y | n]: n

ovios-shell>

In this example, only the initiators with the IP 192.168.0.106, the initiator with IP 192.168.0.107 and the initiator with the IQN iqn.2012-04.org.ovios:9bfhvndth004-tg01 will be allowed to connect to the target.

3.2. Create LUNs

Run 'lun create' and create a LUN. A LUN must be created in a storage pool.

Enter the storage pool name when prompted. Enter a LUN name when prompted.

A LUN can be thin or thick provisioned. Thin provisioning is disabled by default in OviOS because the target doesn't support the DISCARD SCSI command yet.

However, thin LUNs can be created and you can over provision the POOL.

It is strongly recommended to create only thick LUNs to have a better grip on the space available.

Creating a LUN with lun create:

ovios-shell> lun create

Creates a LUN in a storage pool.

Enter storage pool name: OVIOSPOOL

Enter LUN name: lun01

Enter LUN size in g for GB or m for MB etc. Example: 200g | 4T | 1000m: 20g

Create thin or thick provision LUN? (Default: thick) [thin | thick]: thin

Creating thin LUN lun01 in OVIOSPOOL

Success

ovios-shell>

If targets already exist, run 'lun_setup' to create and map the LUN in a single command.

ovios-shell> lun_setup

Enter pool name: OVIOSPOOL

LUN will be created in OVIOSPOOL.

Enter LUN name: lun02

Enter LUN size in g for GB or m for MB etc. Example: 200g | 4T | 1000m: 2TB

Create thin or thick provision LUN? (Default: thick) [thin | thick]: thin

Creating LUN lun02...

would you like to map the LUN to a target? [y|n] y

Enter target name: ovios-tg01

Mapping LUN lun02 to target ovios-tg01 with LUN ID 1....

LUN mapped successfully

Updating iscsi config files...

ovios-shell>

Map the LUNs to targets using 'lun map'. A unique LUN ID will be assigned automatically.

This LUN ID will not be changed.

Run lun list to get a list of LUNs and their properties.

ovios-shell> lun list

NAME             VOLSIZE   USED  AVAIL  LUN:TYPE  LUN:MAPPED  LUN:ID  LUN:TG-NAME

OVIOSPOOL/lun01      20G    12K  7.27G  thin      no          none    none

OVIOSPOOL/lun02       2T    12K  7.27G  thin      yes         1       iqn.2012-04.org.ovios:fuehvhmbh6uv-ovios-tg01

ovios-shell>

The command lun mappings also displays mapped LUNs

ovios-shell> lun mappings

Target 1: iqn.2012-04.org.ovios:fuehvhmbh6uv-ovios-tg01

    LUN information:

        LUN: 1

             /OVIOSPOOL/lun02

ovios-shell>

Map a LUN to an iSCSI Target:

ovios-shell> lun map

Enter pool name: OVIOSPOOL

Enter lun name: lun01

Enter target name: ovios-tg01

Mapping LUN lun01 to target ovios-tg01 with LUN ID 2....

Command returned successfully

Updating iscsi config files...

LUN lun01 mapped to target ID 1 with LUN ID 2.

ovios-shell>

After LUNs have been mapped, run 'iscsi reload' to make them available.

A LUN can only be mapped to one target.

LUNs can also be resized, unmapped from targets, deleted or cloned.

ovios-shell> lun

Usage: lun create | delete | info | list | mappings | map | umap | resize | clone

ovios-shell>

Recommendations:

Use meaningful target names.

Use only thick LUNs.

Use target ACL (when creating targets the command will ask for initiator IP or IQN) to control the iSCSI sessions.

4. Set up NAS (NFS and / or SMB)

OviOS can be used to share volumes via NFS and SMB.

OviOS also supports FTP, but not out-of-the-box, the FTP service must be configured manually.

The vol command

ovios-shell> vol

Usage: vol clone | create | delete | list | resize

ovios-shell>

Create volumes you want to share via SMB or NFS:

Note: if there isn't enough space available in the pool, the volumes will still be created but the requested space won't be reserved.

ovios-shell> vol create

===================================================

= Create a volume inside a storage pool.

===================================================

Enter pool name: OVIOSPOOL

Enter a name for the volume. Letters and numbers in one word only.

Volume name: smbvol

Enter volume size in g for GB or m for MB etc. Example: 200g | 4T | 1000m.

Volume size: 10g

Created volume smbvol in pool OVIOSPOOL.

Setting quota on smbvol in pool OVIOSPOOL

Could not reserve 10G for volume smbvol in OVIOSPOOL

See ovilogs for details

ovios-shell>

ovios-shell> vol list

NAME               USED  AVAIL  MOUNTED  SHARESMB  SHARENFS

OVIOSPOOL          248K  7.27G      yes  off       off

OVIOSPOOL/nfsvol    24K  7.27G      yes  off       off

OVIOSPOOL/smbvol    24K  7.27G      yes  off       off

ovios-shell>

4.1. NFS server

OviOS supports all NFS versions.

The following options can be used to manage the NFS server.

ovios-shell> options nfs

option nfs.threads

option nfs.enable off

option nfs.udp.disable off

option nfs.tcp.disable off

option nfs.idmap off

option nfs4.domain

option nfs.sys.log off

option nfs.disable.vers

option nfs.port

option nfs.debug off

ovios-shell>

Start the NFS server with 'nfs start'

Enable the server to start at boot with the options command

ovios-shell> options nfs.enable on

Changing option: nfs.enable ==> on

ovios-shell> nfs start

  *  Starting NFS statd...                                                                                                                                          [  OK  ]

  *  Starting NFS nfsd...                                                                                                                                           [  OK  ]

  *  Starting NFS mountd...                                                                                                                                         [  OK  ]

  *  Exporting NFS Filesystems...                                                                                                                                   [  OK  ]

ovios-shell>

4.1.1. Export volumes via NFS

Run 'nfs_export' to export volumes NFS clients.

This tool will walk you through the steps to export a volume (an entire pool can also be exported).

One can use the default options, or specify custom options.

If IPs must be specified, use colon to separate them, with no spaces in between.

Example: 10.0.0.1:10.0.0.2:10.0.0.3

Default options are:

rw,sync,no_root_squash,no_subtree_check

Use 'nfs ss' to see what volumes are exported and what options have been used.

ovios-shell> nfs ss

NAME              VALUE

OVIOSPOOL         off

OVIOSPOOL/nfsvol  rw,no_root_squash,no_subtree_check

OVIOSPOOL/smbvol  off

ovios-shell>

To change, or remove exports, use 'nfs_export' as well.

nfs_export is a text UI tool.

4.2. SMB server

OviOS supports SMB versions 1, 2 and 3.

To start the OviOS SMB server, type: 'smb start'. Enable with 'options smb.enabled on'.

ovios-shell> smb start

  *  Starting smbd...                                                      [  OK  ]

  *  Starting winbind...                                                   [  OK  ]

ovios-shell> options smb.enable on

Changing option: smb.enable ==> on

ovios-shell>

The following options manage SMB, WINBIND and NETBIOS.

ovios-shell> options smb

option smb.enable off

option smb.debug.level

option smb.port

ovios-shell> options winbind

option winbind.debug.level

ovios-shell> options netbios

option netbios.enable off

option netbios.debug.level

ovios-shell>

By default NETBIOS is disabled. Enable if needed with:

ovios-shell> options netbios.enable on

Changing option: netbios.enable ==> on

ovios-shell>

4.2.1. Local authentication

In OviOS Linux, SMB requires users to access shares.

These users may then configure guest access via Windows ACLs, however guest access cannot be directly configured in OviOS.

To use local authentication (that means without a Domain Controller), one must create smb local users.

ovios-shell> smbuseradd

Enter share path [Ex: /pool/volume ] to create a homedirectory for this user: OVIOSPOOL/smbvol

Enter username: ovios

new password:

retype new password:

Unix username:        ovios

NT username:

Account Flags:        [U          ]

User SID:             S-1-5-21-3727678225-3779819685-2349632172-1000

Primary Group SID:    S-1-5-21-3727678225-3779819685-2349632172-513

Full Name:

Home Directory:       \\ovios-indt\ovios

HomeDir Drive:

Logon Script:

Profile Path:         \\ovios-indt\ovios\profile

Domain:               OVIOS-INDT

Account desc:

Workstations:

Munged dial:

Logon time:           0

Logoff time:          Wed, 06 Feb 2036 10:06:39 EST

Kickoff time:         Wed, 06 Feb 2036 10:06:39 EST

Password last set:    Mon, 19 Oct 2020 12:43:18 EDT

Password can change:  Mon, 19 Oct 2020 12:43:18 EDT

Password must change: never

Last bad password   : 0

Bad password count  : 0

Logon hours         : FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF

ovios-shell>

'smbuserlist' and 'smbuserdel' are also useful to list or delete smb local users.

ovios-shell> smbuserlist

ovios:1000:

ovios-shell> smbuserdel

Enter username to delete: ovios

Delete home directory for this user (Default: yes)  [y|n]?  y

ovios-shell>

4.2.2. Remote authentication

OviOS SMB Server can join a windows Domain Controller and use AD users for authentication.

Type 'smbovios --join' to start the tool to join a DC.

This tool will guide you through to joining a DC. It will require:

- a domain username with joining privileges (For Ex: Administrator)

- the domain name

- the workgroup as defined in your DC

- the AD computer name (hostname, most cases FQDN)

- a volume path to the root share (/pool/volume)

- IP of the DC

- IP of the DNS and IP of the NTP server (most cases same as DC)

Type 'smbovios --info ' or 'smbovios --unjoin' to get details about the DC or to unjoin the DC.

During the joining process the resolv.conf and nsswitch.conf files are modified. If you require modifications to these files, redo so after joining the DC.

When the --unjoin option is used and the OviOS SMB server leaves a DC, the config files are set back to the state prior to joining the DC.

Type 'smb ad-users' for a list of AD users.

4.2.3. Export volumes via SMB

Type 'smb_export' to export volumes via SMB.

This tool will require a user (can be local smb user or AD user) which will be granted admin rights to this share.

This user will be used to manage the share permissions.

NOTE: ovios is not an SMB user, therefore this user won't be accepted.

Only users listed with 'smb ad-users' and 'smbuserlist' can manage shares.

'smb_export' can also be used to remove shares.

5. Set up replication

Replication can be setup between 2 (or more) OviOS nodes or one OviOS node and another Linux system which runs zfs on linux.

If the destination is not an OviOS system, it must have the 'zfs' and 'zpool' binaries in /usr/sbin.

Before setting up replication, make sure that:

The ssh passwordless authentication must be set up for user root between the nodes.

Make sure the source node can ssh into the destination node with user root without password.

You can achieve this by generating a public ssh key and copying it to the remote node using ssh-copy-id

ovios-shell> linuxcmd

Dropping to the Linux bash shell...

ovios-indt:~ # ssh-keygen

Generating public/private rsa key pair.

Enter file in which to save the key (/root/.ssh/id_rsa): Enter passphrase (empty for no passphrase):

Enter same passphrase again:

Your identification has been saved in /root/.ssh/id_rsa.

Your public key has been saved in /root/.ssh/id_rsa.pub.

The key fingerprint is:

SHA256:CRDFzupr4nij1Ss5pza20qZJpkpcGJJX+W9wF0vY8Tw root@ovios-indt

The key's randomart image is:

+---[RSA 3072]----+

|    +=.  o..     |

| . .... . +o     |

|o..  +.  . oE    |

|..o   =...o  .   |

| . . . +S.       |

|. ...   o        |

| *.o.  .         |

|*+& +.           |

|OX+@o.           |

+----[SHA256]-----+

ovios-indt:~ # ssh-copy-id -i ~/.ssh/id_rsa.pub remote-server

When running a full replication with retadm initiate, the source pool and dataset MUST exist.

On the destination, only the pool must exists, the destination dataset will be created by retadm.

If the destination dataset exists, the command will print an error and exit.

The replication tool is called 'retadm'.

ovios-shell> retadm

    Usage:

        retadm initiate - initiates a new full replication

        retadm inc <poolname/dataset> - runs an incremental replication for poolname/dataset

        retadm modify <poolname/dataset> - allows to modify the destination hostname or IP

        retadm reset <poolname/dataset> - resets all replication properties for poolname/dataset

        retadm status - displays a current status for all datasets in the system, on which

                        replication is enabled. The ones without replication enabled are ignored

        retadm help - prints usage and help menu.

ovios-shell>

5.1. Initial replication

Run 'retadm initiate' .

The interactive tool will ask for the destination hostname or IP, will check if the destination is reachable and passwordless authentication works.

The following example sets up replication for lun1 in OVIOSPOOL, will be sent to remote host with IP 192.168.0.135, and will create a replicated LUN lun01-replicated in the remote pool OVIOSPOOL-REP.

ovios-shell> retadm initiate

Initiates a new replication for a vol or LUN.

Requires ssh authetication to already be configured.

Enter the destination host or IP: 192.168.0.135

Checking 192.168.0.135 is available

192.168.0.135 found and is accessible

Checking if passwordless authentication works to 192.168.0.135

Passwordless authentication tested successfully to 192.168.0.135

Enter the source poolname: OVIOSPOOL

Enter the volume name or LUN name: lun01

Enter the destination poolname: OVIOSPOOL-RET

Enter the destination dataset to be created: lun01-replicated

Checking 192.168.0.135 is available

192.168.0.135 found and is accessible

Checking if passwordless authentication works to 192.168.0.135

Passwordless authentication tested successfully to 192.168.0.135

Created a new snapshot for OVIOSPOOL/lun01 named OVIOSPOOL/lun01@ovios_repl_full-2019-01-08_13:59:07

Started full replication for OVIOSPOOL/lun01 to 192.168.0.135 OVIOSPOOL-RET/lun01-replicated

ovios-shell>

5.2. Incremental replication

Once the initial replication completes, the admin can setup a cron job to schedule replication for multiple volumes and LUNs.

'retadm' logs activity and errors in /var/log/ret.

To schedule replication, use 'edit_cron' from ovios-shell, and add a cron job. For ex:

ovios-shell> edit_cron vim

2019-01-08 14:07:13  INFO listing root's fcrontab

PATH=/bin:/sbin:/usr/bin:/usr/sbin

0 3 * * *   /usr/sbin/logrotate -f /etc/logrotate.conf

*/30 * * * * /sbin/retadm inc OVIOSPOOL/lun01

This line (*/30 * * * * /sbin/retadm inc OVIOSPOOL/lun01) means OVIOSPOOL/lun01 will be replicated every 30 minutes to the destination we already setup with "retadm initiate"

To modify the destination for a dataset, use 'retadm modify'.

5.3. Break replication

Breaking a replication will remove the replication relationship between source and destination and will remove base snapshots on source and destination.

The source and destination volume or LUNs will not be removed.

ovios-shell> retadm reset OVIOSPOOL/lun01

This will break replication for retpool/vol0 and delete the base snapshot.

It will not remove the destination dataset, but will remove the destination base snapshot

Enter YES to continue: YES

Finished resetting replication for OVIOSPOOL/lun01

ovios-shell>

6. Disaster recovery (DR)

DR refers to the possibility to easily and quickly make production data accessible to clients during a period when the production system is unavailable.

To make sure this is possible, always use an OviOS remote system where you replicate your critical volumes and LUN.

The replicated shares and LUNs are always available on the destination system.

The destination system's configuration can be synced with the source automatically, so that in a DR scenario all shares, LUNs and iSCSI Targets are available immediately.

For this to work, the pool name on the source and destination must be identical, and all shares and LUNs on the destination must have the same name as the source.

If these requirements are met, run 'sync-config dest <destination host or IP>

This will sync all users, groups, hosts, SMB settings, iSCSI settings to the destination.

The network settings are , for obvious reasons, not synced, as the source has a different hostname and IP addresses.

Therefor, a scheduled cron job should be setup to periodically sync the config.

For ex: */30 * * * * /sbin/sync-config dest-hostname

Once a DR scenario occurs and the remote system is required to serve production data, via iSCSI, SMB and NFS, and sync-config is up to date (all users, iSCSI settings, NFS shares, SMB users and shares) simply point the clients to the remote system IP or hostname.

In cases when this is not a true DR system, and the destination host requires different local settings, then the admin must prepare the config manually.

Create local users, create SMB users, join to an AD and so on.

There is a tool called ovios_restore that can be used on the destination to automatically create the targets and map the replicated LUNs to the targets, by not removing any targets which exist already on the system.

However, the LUNs will be mapped with their original LUN IDs, so in this case the admin must be carefull not to have duplicate LUN IDs, and correct those manually if needed.