When attempting to resize and old ext4 Partition that was created without the 64bit flag, resize2fs 1.42 will fail if the new size is or exceeds 16TiB.
$ resize2fs -p /dev/mapper/target-device
resize2fs: New size too large to be expressed in 32 bits
I do not want to copy the files to an external medium. I do not want to risk data loss either. How can i resize the volume safely?
I have a fresh ext4 partition, which means I just formated it with mkfs.ext4 -m 0.1 /dev/mapper/abak-home, and there's already 27G space used. Setting reserved root space (-m) to 0 didn't have any effect.
I'm using LVM but I don't think that LVM should have any effect on this. Ubuntu version is 12.04 LTS.
# df -h Filesystem Size Used Avail Use% Mounted on ... /dev/mapper/abak-home 1.8T 27G 1.8T 2% /home
Then I tried formating partition with ext3 and the result is much better:
# df -h Filesystem Size Used Avail Use% Mounted on ... /dev/mapper/abak-home 1.8T 196M 1.8T 1% /home
Anyway, why the difference and how can I fix this?
What are the big differences between ext3 and ext4 from a generic user's perspective? I heard that sticking with ext3 is wiser. Is that true?
EDIT: One thing I want to note is that I am a dual OS user (Windows & Ubuntu), so not being able to mount a drive (ext4) from Windows is a big negative for me. But, ext3 has this privilege.
When creating a file system ( mkfs ...) the file system reserves 5% of the space for its own use because, according to man tune2fs:
Reserving some number of filesystem blocks for use by privileged processes is done to avoid filesystem fragmentation, and to allow system daemons, such as syslogd(8), to continue to function correctly after non-privileged processes are prevented from writing to the filesystem.
But with large drives 5% is quite a lot of space.
I have 4x1.5 TB drives for data storage (the OS runs on a separate disk), so the default setting would reserve 300 GB, which is an order of magnitude more than the the entire OS drive.
The reserved space can be tweaked, but what is a reasonable size for a data disk? Can I set it to zero, or could that lead to issues with fragmentation?
With previous versions of Ubuntu (using Ext3 filesystem) I used to tune it for better performance with noticeable results by setting the noatime parameter in /etc/fstab.
Is it still worth it to do that with the Ext4 filesystem, which is now default in Ubuntu? If so, does the procedure changed in some way?
An example of this tuning can be found here.