Expand ZFS Pools on Nodes

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Introduction

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Prerequisites

• SSH access to the node. See Enable and Disable SSH Access for Nodes.
• The node is configured with ZFS raid level none (eve_install_zfs_with_raid_level=none). This procedure does not apply to nodes configured with raid1, raid5, or raid6.
• EVE-OS 8.11.0 or greater.
• A new disk installed in the node, or a previously unused disk that has not been assigned to any pool.

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SSH into the Node

1. Connect to the node as root:
   ssh -i YOUR_PRIVATE_KEY_PATH root@DEVICE_IP
   
   For example:
   ssh -i ~/.ssh/id_rsa root@172.16.8.194
   
   Example response:
   EVE is Edge Virtualization Engine
   Take a look around and don't forget to use eve(1).
   862bab0f-a567-4fc2-98b1-c82c77cf74c9:~#
   
2. Run eve enter to enter the pillar namespace:
   eve enter
   
   Example response:
   (ns: pillar) 862bab0f-a567-4fc2-98b1-c82c77cf74c9:/#
   
3. Before making changes, review the current pool state and size:
   zpool list
   
   Example response:
   NAME      SIZE  ALLOC   FREE  CKPOINT  EXPANDSZ   FRAG    CAP  DEDUP    HEALTH  ALTROOT
   persist   230G  18.0G   212G        -         -    14%     7%  1.00x    ONLINE  -
   
   zpool status
   
   Example response:
   pool: persist
    state: ONLINE
   config:
   	NAME        STATE     READ WRITE CKSUM
   	persist     ONLINE       0     0     0
   	  sda9      ONLINE       0     0     0
   errors: No known data errors
   

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Find the Unused Disk

1. Copy the script content from the Script Reference section into a file on the node. The following example uses vi:
   vi /tmp/expand_raid0_pool_to_device.sh
   
   Press i to enter insert mode, paste the script content, press Esc, then type :wq to save and exit.
2. Make the script executable:
   chmod +x /tmp/expand_raid0_pool_to_device.sh
   
3. Run the script with the -d flag to identify unused disks:
   /tmp/expand_raid0_pool_to_device.sh -d ()
   
   If an unused disk is available, the output shows its device path and size, for example:
   Found unused: /dev/sdb 58.3G
   
   If no unused disk is found, stop here. Verify that the disk is physically installed and recognized by the operating system before continuing.

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Expand the Pool

1. Run the script with the -e flag and the device path of the disk you want to add:
   /tmp/expand_raid0_pool_to_device.sh -e /dev/sdb
   
2. When prompted, enter the device path again to confirm:
   Are you sure you want to expand pool to device /dev/sdb? If so, enter the device path again.
   /dev/sdb
   
   A successful expansion returns:
   Success: expand complete
   
3. Exit the pillar namespace and your SSH session:
   exit
   exit
   

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Verify the Expansion

zpool status

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
errors: No known data errors

zpool list

NAME      SIZE  ALLOC   FREE  CKPOINT  EXPANDSZ   FRAG    CAP  DEDUP    HEALTH  ALTROOT
persist   288G  18.0G   270G        -         -    11%     6%  1.00x    ONLINE  -

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Troubleshoot Disk Wipe Errors

invalid vdev specification

use '-f' to override the following errors:

/dev/sdb1 contains a filesystem of type 'vfat'

wipefs -a /dev/sdb

/dev/sdb: 8 bytes were erased at offset 0x00000200 (gpt): 45 46 49 20 50 41 52 54
/dev/sdb: 8 bytes were erased at offset 0x1e00ffe00 (gpt): 45 46 49 20 50 41 52 54
/dev/sdb: 2 bytes were erased at offset 0x000001fe (PMBR): 55 aa
/dev/sdb: calling ioctl to re-read partition table: No error information

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Script Reference

#!/bin/sh
usage() {
	echo "Usage $0 [OPTION]"
	echo " Expand EVE-OS ZFS pool to a new device"
	echo " "
	echo " -d Finds unused device"
	echo " -e   Expands raid0 pool to new device"
	exit 1
}

do_find_device=0
do_expand=0
device=""
while getopts "de:h" opt;
do
	case "${opt}" in
		d)
			do_find_device=1
			;;
		e)
			do_expand=1
			device=${OPTARG}
			;;
		*)
			usage
			;;
	esac
done
if [ $do_expand -eq 0 ] && [ $do_find_device -eq 0 ]; then
	usage
fi

if [ $do_find_device -eq 1 ]; then
	found_devs=$(lsblk -nd -e 1,230,43 -o NAME)
	for found_dev in $found_devs; do
		full_dev="/dev/${found_dev}"
		mount | grep -q $full_dev
		mounted=$?
		if [ $mounted -eq 1 ]; then
			zpool status -P | grep -q $full_dev
			in_pool=$?
			if [ $in_pool -eq 1 ]; then
				info=$(lsblk -o SIZE -nd $full_dev)
				echo "Found unused: $full_dev $info"
			fi
		fi
	done
	exit 0
fi

if [ $do_expand -eq 1 ]; then
	grep -q eve_install_zfs_with_raid_level=none /proc/cmdline
	if [ $? -ne 0 ]; then
		echo "Error: invalid eve zfs raid level detected on this device."
		exit 1
	fi

	if [ ! -b $device ]; then
		echo "Error: disk not found, exiting. Please call customer support."
		exit 1
	fi

	read -p "Are you sure you want to expand pool to device ${device}? If so, enter the device path again. " choice
	case "$choice" in
		"$device" )
			zpool add persist $device
			if [ $? -eq 0 ]; then
				zpool set autoexpand=on persist
				if [ $? -eq 0 ]; then
					echo "Success: expand complete"
				fi
		fi
		exit 0
		;;
	* )
		echo "Error: device path mismatch, exiting without action."
		exit 1
		;;
	esac
fi

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Next Steps