Hello,
we are dealing with many directories generated by our application exhausting directory limit of Ext3 filesystem. Ext4 is promising higher limit of subdirectories per directory. We made bit of research on web regarding stability of Ext4 filesystem on SLES 11.2 and there are some problems regarding Ext4. So we are courious as Ext4 is offically supported filesystem by Suse - is it safe enough for production enviroment and are there any tips regarding use of Ext4.
Thanks a lot!
Hi nkpvrbicky,
according to the release notes (https://www.suse.com/releasenotes/x86_64/SUSE-SLES/11-SP3/), ext4 is fully supported as a file system. But in order to gain r/w access, you’ll even have to separately activate the according feature during module load:
[QUOTE]
[h=3]14.4.2 ext4: Runtime Switch for Write Support[/h]
The SLE 11 SP3 kernel contains a fully supported ext4 file system module, which provides read-only access to the file system.
Read-write access to an ext4 file system can be acquired by setting the rw kernel module parameter to 1, either through module load time options or after module load through the kernel sysctl interface. Be aware that this action will render the kernel module and the kernel as the whole as unsupported upon first read-write mount of an ext4 file system.
ext4 is not supported for the installation of the SUSE Linux Enterprise operating system.
Since SUSE Linux Enterprise 11 SP2 we support offline migration from ext4 to the supported btrfs file system.[/QUOTE]
The Ext4 Howto at https://ext4.wiki.kernel.org/index.php/Ext4_Howto states that “It’s safe to use it in production environments, but as any piece of software, it has bugs (which are more likely to be hit in the first stable versions). Any known critical bug will be quickly fixed.”
Are you actually limited to SP2, or was that a “reference to earlier statements on the web”?
Regards,
Jens
ext4 is not supported on SLES. If you need something that works beyond
ext3 use XFS which is free from SUSE (unlike some other distributions
which charge for access to it). SUSE’s strategy, according to SUSECon
last year as I recall (the 2013 SUSECon is coming up in about two months
now) is to use XFS for the present and btrfs in the future. As a result
ext4 is not available on SLES.
https://www.suse.com/products/server/technical-information/
Good luck.
On 06/09/2013 11:54, jmozdzen wrote:
[color=blue]
ext4 is
fully supported as a file system.[/color]
For read-only access to the file system but not read-write.
Simon
SUSE Knowledge Partner
Hi Simon,
[QUOTE=smflood;15811]On 06/09/2013 11:54, jmozdzen wrote:
[COLOR=blue]
ext4 is
fully supported as a file system.[/COLOR]
For read-only access to the file system but not read-write.
Simon[/QUOTE]
yes, hence the quote from the release notes - the third sentence is quite explicit: “Be aware that this action will render the kernel module and the kernel as the whole as unsupported upon first read-write mount of an ext4 file system.”
In addition, it is not supported to create an ext4 boot partition - but usually that’d have to be r/w, so that consequence is almost obvious 
Regards,
Jens