Master Linux Disk Quota, LVM, and RAID: Step-by-Step Configuration Guide

When multiple users share a Linux server, disk quota helps enforce fair disk usage, while LVM and RAID provide flexible storage management.

Quota configuration

Quota limits the amount of disk space and number of files per user or group, with soft and hard limits and a grace period.

Quota limit types: • Limit space usage for users and groups • Limit number of files for users and groups

Quota limit levels: • Soft limit – can be exceeded temporarily, triggers warnings and a grace period. • Hard limit – absolute limit, cannot be exceeded. • Grace days – default 7 days before soft‑excess is reclaimed.

Install quota tools with yum install -y quota.

Check kernel support

# cat /boot/config-... | grep CONFIG_QUOTA
CONFIG_QUOTA=y
CONFIG_QUOTA_NETLINK_INTERFACE=y
CONFIG_QUOTA_TREE=y
CONFIG_QUOTACTL=y
CONFIG_QUOTACTL_COMPAT=y

Verify mount options

# dumpe2fs -h /dev/vdb | grep "Default mount options"
Default mount options:    user_xattr acl
# Ensure usrquota and grpquota are present, otherwise remount with them.
# mount -o remount,usrquota,grpquota /dev/vdb

Generate quota files

# quotacheck -ugv /dev/vdb

Edit quotas

# edquota -u lyshark
# edquota -g temp

Enable/disable quota

# quotaon -augv
# quotaoff -augv

View quotas

# quota -ugvs

LVM (Logical Volume Manager)

LVM aggregates physical volumes (PV) into volume groups (VG) and creates logical volumes (LV) that can be resized and snapshotted.

Create physical volumes

# pvcreate /dev/sdb /dev/sdc /dev/sdd

Create a volume group

# vgcreate -s 4M my_vg /dev/sdb /dev/sdc

Extend the volume group

# vgextend my_vg /dev/sdd

Create a logical volume

# lvcreate -L 10G -n my_lv my_vg

Format and mount the LV

# mkfs.ext4 /dev/my_vg/my_lv
# mount /dev/my_vg/my_lv /LVM

Resize LV (increase)

# lvextend -L +5G /dev/my_vg/my_lv
# resize2fs -f /dev/my_vg/my_lv

Resize LV (decrease)

# umount /dev/my_vg/my_lv
# e2fsck -f /dev/my_vg/my_lv
# resize2fs -f /dev/my_vg/my_lv 10G
# lvreduce -L 10G /dev/my_vg/my_lv
# mount /dev/my_vg/my_lv /LVM

LV snapshot

# lvcreate -s -n mylv_back -L 200M /dev/my_vg/my_lv

RAID (Redundant Array of Independent Disks)

RAID provides redundancy and performance. Common levels include RAID 0 (striping), RAID 1 (mirroring), RAID 10 (mirrored striping), and RAID 5 (distributed parity).

Create RAID 5 with mdadm

# mdadm --create --auto=yes /dev/md0 --level=5 --raid-devices=3 --spare-devices=1 /dev/sd{b,c,d,e}

Format and mount the RAID device

# mkfs.ext4 /dev/md0
# mkdir /RAID
# mount /dev/md0 /RAID

RAID maintenance (fail, remove, add)

# mdadm --manage /dev/md0 --fail /dev/sdb
# mdadm --manage /dev/md0 --remove /dev/sdb
# mdadm --manage /dev/md0 --add /dev/sdb