If you are using hot swappable hard disk and created new partition using fdisk then you need to reboot Linux based system to get partition recognized. Without reboot you will NOT able to create filesystem on your newly created or modified partitions with the mke2fs command.
However with partprobe command you should able to create new file system without a reboot. It is a program that informs the operating system kernel of partition table changes, by requesting that the operating system re-read the partition table.
After fdisk session just type command:
# partprobe
Now you will able to create filesystem on with the mke2fs command.
Inform the OS of partition table changes
partprobe command is part of GNU parted software. parted is a disk partitioning and partition resizing program. It allows you to create, destroy, resize, move and copy ext2, ext3, linux-swap, FAT, FAT32, and reiserfs partitions. It can create, resize and move Macintosh HFS partitions, as well as detect jfs, ntfs, ufs, and xfs partitions. It is useful for creating space for new operating systems, reorganising disk usage, and copying data to new hard disks.
Install parted
In order to use partprobe command you need to install parted:
If you are using Debian / Ubuntu Linux, enter:
# apt-get install parted
OR if you are using RHEL version <= 4, enter:
# up2date parted
OR if you are using Fedora Linux / CentOS / RHEL 5, enter:
# yum install parted
See also:
=> See official parted home page for download and other information.
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- Last Updated: Oct/19/2007



{ 11 comments… read them below or add one }
Its a very good tip that can be used in a production evironment without any downtime
Thank you!
And to make this a bit more googlable:
fdisk printout: “Calling ioctl() to re-read partition table. WARNING: Re-reading the partition table failed with error 16: Device or resource busy”
When partprobe isn’t available you can also (sometimes) use:
# hdparm -z /dev/sdX
which will re-read that device’s partition table.
Thank You!
You saved me from having to restart my server!
(restarting is a real pain in the neck)
Thanks a lot !
And in order to install parted for gentoo users :
emerge -av parted
;)
Thanks for the tips (LINUXTITLI, Jason) and also thanks domen for making this more googlable!
Created a new partition from unformatted disk space (got error in re-reading the partition table: device busy) , partprobed, mkfs.ext3′d, e2labeled and mounted!
No reboot needed, thanks again. :)
I found this website while I was trying to figure out what the difference between the three ways I’ve found so far (partprobe, hdparm -z /dev/disk, and blockdev –rereadpt /dev/disk) is.
Boy was I happy to find this post. Just added a new partition to my gentoo production server after 463 days uptime and stumbled across the above mentioned ioctl warning. Thanks guys for the post and the comments :)
Never was able to get the disk formatting re-read using partprobe. Had to reboot servers. May be to note that I am working on Redhat clusters with gfs. That shouldn’t matter much, as I run partprobe on both nodes.
on RH systems you may need to run udevstart after partprobe
A 4th way is:
echo 1 > /sys/block/sdc/device/rescan
And follow dmesg to see the kernel rescan the disk. I found this worked on a server that partprobe did not.