> ## Documentation Index
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> Use this file to discover all available pages before exploring further.

> ## Agent Instructions
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> Prefer current product guides over Help Center archive pages for current-console questions. Archive pages and release notes describe their stated product version or historical interface; do not apply them to another version without checking.
> Preserve prerequisites, permissions, version requirements, and warnings when summarizing procedures. Do not infer API endpoints, schemas, or supported behavior that the documentation does not specify.

# Configure grub.cfg for EVE-OS Multidisk Installation

> How to customize grub.cfg to control disk partitioning during EVE-OS installation, including separate installation and persistence disks and ZFS RAID configurations.

## Introduction

By default, EVE-OS selects installation and persistence disks automatically. You can override these defaults by customizing the `grub.cfg` file before running the EVE-OS installer. This lets you explicitly assign the disk for the EVE-OS installation (`eve_install_disk`) and the disk (or disks) for the persistent application storage volume (`eve_persist_disk`). It also lets you configure ZFS RAID levels for fault-tolerant or high-capacity persistence storage.

All procedures require access to the CONFIG partition of the EVE-OS installer USB drive to edit `grub.cfg`. Edit the file at the root of the CONFIG partition (named `EVE`), alongside the `server` and `grub.cfg.tmpl` files. Do not edit `EFI/BOOT/grub.cfg` — changes there do not persist after reboot.

If you are building a custom installer ISO instead of writing to a USB drive, you must place your `grub.cfg` in a local overrides directory and mount that directory when running the build command. If you run the build without mounting the overrides directory, EVE-OS uses default values and your disk and storage configurations will not take effect.

```text theme={"dark"}
docker run -v ~/eve-overrides/:/in --platform=linux/amd64 lfedge/eve:<version> installer_iso > installer.iso
```

To run `zpool` commands for verification, access the pillar container using:

```text theme={"dark"}
eve enter pillar
```

## Separate Installation and Persistence Disks

This configuration installs EVE-OS on one disk and dedicates a separate disk entirely to the `/persist` volume. No ZFS is used.

### Prerequisites

* A minimum of 2 distinct physical storage devices.
* The kernel device names for your target disks (for example, `nvme0n1`, `sda`).

### Scenario

This example uses the following two-disk setup:

* `/dev/nvme0n1` — EVE-OS installation disk.
* `/dev/sda` — persistence disk.

### Modify grub.cfg

Open `grub.cfg` from the CONFIG partition (labeled `EVE`) of your installer USB drive — the same partition that contains the `server` and `grub.cfg.tmpl` files. Add the following `dom0_extra_args` line:

```text theme={"dark"}
set_global dom0_extra_args "$dom0_extra_args eve_install_disk=nvme0n1 eve_persist_disk=sda"
```

The non-commented content of the modified file should resemble the following structure. You can verify this by running `cat grub.cfg | grep -v ^#` on the file:

```text theme={"dark"}
set_getty
set_global dom0_console "console=tty0 console=ttyS0"
set_global dom0_extra_args "$dom0_extra_args eve_install_disk=nvme0n1 eve_persist_disk=sda"
```

Save the file and boot the node from the USB drive. The installer applies the disk assignments automatically.

### Verify

After installation and reboot, confirm disk assignments using the following commands.

Check disk partitions with `lsblk`:

```text theme={"dark"}
~# lsblk | grep -e nvme0n1 -e sda
sda         254:0    0      20G  0 disk
└─sda1      254:1    0      20G  0 part /persist
nvme0n1     254:16   0   476.9G  0 disk
├─nvme0n1p1 254:17   0      36M  0 part
├─nvme0n1p2 254:18   0     512M  0 part /usr/bin/service
├─nvme0n1p3 254:19   0     512M  0 part
└─nvme0n1p3 254:20   0       1M  0 part
```

The persistence partition (`sda1`) is on `/dev/sda` and mounted to `/persist`. EVE-OS partitions are exclusively on `/dev/nvme0n1`.

Check the kernel command line to confirm the disk arguments were applied:

```text theme={"dark"}
~# cat /proc/cmdline
```

The output should contain `eve_install_disk=nvme0n1` and `eve_persist_disk=sda`.

Check mounted filesystems:

```text theme={"dark"}
~# mount | grep "/hostfs "
/dev/nvme0n1p2 on /hostfs type squashfs (ro,relatime,errors=continue)

~# mount | grep "/persist "
/dev/sda1 on /hostfs/persist type ext4 (rw,noatime,dirsync)
/dev/sda1 on /persist type ext4 (rw,noatime,dirsync)
```

## ZFS with Integrated Persistence — RAID-0 (Stripe)

This configuration installs EVE-OS on a specified disk and creates a ZFS persistence pool (RAID-0/stripe) that spans multiple disks, including free space from the installation disk.

### Prerequisites

* Minimum 1 disk. No maximum (limited by hardware).

### Scenario

This example uses three disks: `sda`, `sdb`, and `sdc`.

* EVE-OS installs on `/dev/sda`.
* The persistence pool spans free space from `/dev/sda`, `/dev/sdb`, and `/dev/sdc`.

### Modify grub.cfg

Open `grub.cfg` from the CONFIG partition (labeled `EVE`) of your installer USB drive. Add the appropriate `dom0_extra_args` line for your disk count.

**Multi-disk setup (sda, sdb, sdc):**

```text theme={"dark"}
set_global dom0_extra_args "$dom0_extra_args eve_install_zfs_with_raid_level=none eve_install_disk=sda eve_persist_disk=sda,sdb,sdc"
```

**Single-disk setup (sda only):**

```text theme={"dark"}
set_global dom0_extra_args "$dom0_extra_args eve_install_zfs_with_raid_level=none eve_install_disk=sda"
```

The `eve_persist_disk` parameter is not required when using a single disk.

**Full grub.cfg example (multi-disk):**

```text theme={"dark"}
# You can put your GRUB overrides into conf/grub.cfg
set_getty
set_global dom0_console "console=tty0 console=ttyS0"
## set this to install raid0 for:
## - eve on sda
## - persist partition on sda, sdb, sdc
set_global dom0_extra_args "$dom0_extra_args eve_install_zfs_with_raid_level=none eve_install_disk=sda eve_persist_disk=sda,sdb,sdc"
```

### Verify

After installation and reboot, verify the ZFS pool and filesystem layout.

Check the ZFS pool status. The `persist` pool should show all three disk partitions online:

```text theme={"dark"}
(ns: pillar) linuxkit-525400dcb57e:/# zpool status -v
  pool: persist
 state: ONLINE
config:
        NAME        STATE     READ WRITE CKSUM
        persist     ONLINE       0     0     0
          sda9      ONLINE       0     0     0
          sdb       ONLINE       0     0     0
          sdc       ONLINE       0     0     0
```

Check that EVE-OS is installed on `sda` (not ZFS):

```text theme={"dark"}
(ns: pillar) linuxkit-525400dcb57e:/# mount | grep "/hostfs "
/dev/sda2 on /hostfs type squashfs (ro,relatime,errors=continue)
```

## ZFS with RAID-1 (Mirror) Persistence

This configuration installs EVE-OS on one disk and creates a RAID-1 mirrored ZFS persistence pool across two separate disks for fault tolerance.

### Prerequisites

* Minimum 3 disks (1 for EVE-OS, 2 for the mirror pool).

### Scenario

This example uses three disks: `sda`, `sdb`, and `sdc`.

* EVE-OS installs on `/dev/sda`.
* The `/persist` volume is a RAID-1 mirror across `/dev/sdb` and `/dev/sdc`.

### Modify grub.cfg

Open `grub.cfg` from the CONFIG partition (labeled `EVE`) of your installer USB drive. Add the following `dom0_extra_args` line:

```text theme={"dark"}
set_global dom0_extra_args "$dom0_extra_args eve_install_zfs_with_raid_level=raid1 eve_install_disk=sda eve_persist_disk=sdb,sdc"
```

**Full grub.cfg example:**

```text theme={"dark"}
set_getty
set_global dom0_console "console=tty0 console=ttyS0"
## set this to install raid1 for:
## - eve on sda
## - persist partition on sdb and sdc
set_global dom0_extra_args "$dom0_extra_args eve_install_zfs_with_raid_level=raid1 eve_install_disk=sda eve_persist_disk=sdb,sdc"
```

### Verify

Check the ZFS pool status. The output should show `mirror-0 ONLINE` with both disks attached:

```text theme={"dark"}
(ns: pillar) linuxkit-525400dcb57e:/# zpool status -v
  pool: persist
 state: ONLINE
config:
        NAME        STATE     READ WRITE CKSUM
        persist     ONLINE       0     0     0
          mirror-0  ONLINE       0     0     0
            sdb     ONLINE       0     0     0
            sdc     ONLINE       0     0     0
errors: No known data errors
```

Check the kernel command line to confirm the arguments:

```text theme={"dark"}
~# cat /proc/cmdline
```

The output should contain `eve_install_zfs_with_raid_level=raid1`, `eve_install_disk=sda`, and `eve_persist_disk=sdb,sdc`.

## ZFS with RAID-Z1 (RAID-5) Persistence

This configuration creates a fault-tolerant RAID-Z1 ZFS persistence pool across three dedicated disks, tolerating one disk failure.

### Prerequisites

* Minimum 4 disks (1 for EVE-OS installation, 3 for the RAID-Z1 pool).

### Scenario

This example uses four disks: `sda`, `sdb`, `sdc`, and `sdd`.

* EVE-OS installs on `/dev/sda`.
* The `/persist` volume is a RAID-Z1 pool across `/dev/sdb`, `/dev/sdc`, and `/dev/sdd`.

### Modify grub.cfg

Open `grub.cfg` from the CONFIG partition (labeled `EVE`) of your installer USB drive. Add the following `dom0_extra_args` line:

```text theme={"dark"}
set_global dom0_extra_args "$dom0_extra_args eve_install_zfs_with_raid_level=raid5 eve_install_disk=sda eve_persist_disk=sdb,sdc,sdd"
```

**Full grub.cfg example:**

```text theme={"dark"}
# File: grub.cfg
set_getty
set_global dom0_console "console=tty0 console=ttyS0"
## set this to install raid5 for:
## - eve on sda
## - persist partition on sdb, sdc, and sdd
set_global dom0_extra_args "$dom0_extra_args eve_install_zfs_with_raid_level=raid5 eve_install_disk=sda eve_persist_disk=sdb,sdc,sdd"
```

### Verify

Check the ZFS pool status. The output should show `raidz1-0 ONLINE` with three disks attached:

```text theme={"dark"}
(ns: pillar) linuxkit-525400dcb57e:/# zpool status -v
  pool: persist
 state: ONLINE
config:
        NAME        STATE     READ WRITE CKSUM
        persist     ONLINE       0     0     0
          raidz1-0  ONLINE       0     0     0
            sdb     ONLINE       0     0     0
            sdc     ONLINE       0     0     0
            sdd     ONLINE       0     0     0
```

Check the kernel command line to confirm the arguments:

```text theme={"dark"}
~# cat /proc/cmdline
```

The output should contain `eve_install_zfs_with_raid_level=raid5`, `eve_install_disk=sda`, and `eve_persist_disk=sdb,sdc,sdd`.

Check that EVE-OS itself is not running under ZFS:

```text theme={"dark"}
(ns: pillar) linuxkit-525400dcb57e:/# mount | grep "/hostfs "
/dev/sda2 on /hostfs type squashfs (ro,relatime,errors=continue)
```

## ZFS with RAID-Z2 (RAID-6) Persistence

This configuration creates a highly resilient RAID-Z2 ZFS persistence pool across four dedicated disks, tolerating two simultaneous disk failures.

### Prerequisites

* Minimum 5 disks (1 for EVE-OS installation, 4 for the RAID-Z2 pool).

### Scenario

This example uses five disks: `sda`, `sdb`, `sdc`, `sdd`, and `sde`.

* EVE-OS installs on `/dev/sda`.
* The `/persist` volume is a RAID-Z2 pool across `/dev/sdb`, `/dev/sdc`, `/dev/sdd`, and `/dev/sde`.

### Modify grub.cfg

Open `grub.cfg` from the CONFIG partition (labeled `EVE`) of your installer USB drive. Add the following `dom0_extra_args` line:

```text theme={"dark"}
set_global dom0_extra_args "$dom0_extra_args eve_install_zfs_with_raid_level=raid6 eve_install_disk=sda eve_persist_disk=sdb,sdc,sdd,sde"
```

**Full grub.cfg example:**

```text theme={"dark"}
# You can put your GRUB overrides into conf/grub.cfg
set_getty
set_global dom0_console "console=tty0 console=ttyS0"
## set this to install raid6 for:
## - eve on sda
## - persist partition on sdb, sdc, sdd and sde
set_global dom0_extra_args "$dom0_extra_args eve_install_zfs_with_raid_level=raid6 eve_install_disk=sda eve_persist_disk=sdb,sdc,sdd,sde"
```

### Verify

Check the ZFS pool status. The output should show `raidz2-0 ONLINE` with four disks attached:

```text theme={"dark"}
(ns: pillar) linuxkit-525400dcb57e:/# zpool status -v
  pool: persist
 state: ONLINE
config:
        NAME        STATE     READ WRITE CKSUM
        persist     ONLINE       0     0     0
          raidz2-0  ONLINE       0     0     0
            sdb     ONLINE       0     0     0
            sdc     ONLINE       0     0     0
            sdd     ONLINE       0     0     0
            sde     ONLINE       0     0     0
errors: No known data errors
```

Check the kernel command line to confirm the arguments:

```text theme={"dark"}
~# cat /proc/cmdline
```

The output should contain `eve_install_zfs_with_raid_level=raid6`, `eve_install_disk=sda`, and `eve_persist_disk=sdb,sdc,sdd,sde`.

Check that EVE-OS is installed on `sda` and is not part of the ZFS pool:

```text theme={"dark"}
(ns: pillar) linuxkit-525400dcb57e:/# mount | grep "/hostfs "
/dev/sda2 on /hostfs type squashfs (ro,relatime,errors=continue)
```

## Next Steps

> [card] [Get EVE-OS](https://zededa.mintlify.site/new-ui/infrastructure-services/eve-os-installation/get-eve-os.md)
>
> Build an EVE-OS image with a custom `grub.cfg`.

> [card] [Install EVE-OS onto an Edge Device](https://zededa.mintlify.site/new-ui/infrastructure-services/eve-os-installation/install-eve-os.md)
>
> Complete the installation procedure.

> [card] [Expand ZFS Pools on Nodes](https://zededa.mintlify.site/new-ui/infrastructure-services/nodes/expand-zfs-pools.md)
>
> Add capacity to an existing ZFS pool after installation.