RHEL: Reserved space on a ext2/ext3/ext4 filesystem

# Tested on RHEL 6 & 7

# By default, when creating a new ext2/ext3/ext4 filesystem, five percent of the partition
# is reserved for the superuser, allowing root to carry out administrative tasks on the
# filesystem in the eventuality that F.S. becomes full.

# In the case of large partitions 5% may represent a lot of space so the percentage of
# reserved space may be reduced to the minimum, which is 1%


# We will use 'tune2fs' command with '-m' option, that allows us to modify it on line

#
In this case I'm not saving much space as I'm using a small filesystem of only 1GB !

mkfs.ext3 /dev/rootvg/lv_apps  
# Valid for 'mkfs.ext2' and 'mkfs.ext4' commands too
   [...]
   13107 blocks (5.00%) reserved for the super user

   [...]

tune2fs -l /dev/rootvg/lv_apps | grep -i "block count"
   Block count:              262144
   Reserved block count:     13107

mount /dev/rootvg/lv_apps /apps


df -k /apps
   Filesystem                 1K-blocks  Used Available Use% Mounted on
   /dev/mapper/rootvg-lv_apps    999320  1320    945572   1% /apps


# Let's reduce reserved space to 1%:

tune2fs -m 1 /dev/rootvg/lv_apps
   tune2fs 1.42.9 (28-Dec-2013)
   Setting reserved blocks percentage to 1% (2621 blocks)

tune2fs -l /dev/rootvg/lv_apps | grep -i "block count"
   Block count:              262144
   Reserved block count:     2621

# Note that available space value is higher than before:

df -k /apps
   Filesystem                 1K-blocks  Used Available Use% Mounted on
   /dev/mapper/rootvg-lv_apps    999320  1320    987516   1% /apps
0 (0)
Article Rating (No Votes)
Rate this article
Attachments
There are no attachments for this article.
Comments
There are no comments for this article. Be the first to post a comment.
Full Name
Email Address
Security Code Security Code
Related Articles RSS Feed
RHEL : How to deal with “CLOSE_WAIT” and “TIME_WAIT” connection
Viewed 25150 times since Thu, Feb 14, 2019
10 Linux nslookup Command Examples for DNS Lookup
Viewed 9937 times since Sun, Sep 30, 2018
rabbitmq Troubleshooting TLS-enabled Connections
Viewed 2081 times since Sun, Dec 6, 2020
Linux Linux Network Statistics Tools / Commands
Viewed 8850 times since Mon, Sep 21, 2020
7 Tips – Tuning Command Line History in Bash
Viewed 4887 times since Fri, Jul 5, 2019
ZFS: Verify/change properties of a zfs filesystem
Viewed 2322 times since Sun, Jun 3, 2018
www.unixarena.com
Viewed 2208 times since Fri, Jul 27, 2018
How To: Create Self-Signed Certificate – OpenSSL
Viewed 2720 times since Mon, Feb 18, 2019
stunnel How To Set Up an SSL Tunnel Using Stunnel on Ubuntu
Viewed 1428 times since Sun, Dec 6, 2020
ZFS: Remove an existing zfs filesystem
Viewed 1915 times since Sun, Jun 3, 2018