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.