[DRBD-user] Ext4

Diego Remolina diego.remolina at physics.gatech.edu
Wed Oct 14 19:06:08 CEST 2009

Note: "permalinks" may not be as permanent as we would like,
direct links of old sources may well be a few messages off.

I was using it without any issues on RHEL5.3 on two drbd volumes. The 
first one was 12TB, the second 4TB.

I had no issues whatsoever related to drbd and the file system. I rolled 
back to ext3 on my file systems when I found what turned out to be an 
NFS bug in the 5.4 release kernel, where the permissions and times for 
new files were getting screwed up very badly.

I originally thought that ext4 was at fault (being a Tech preview in 
RHEL5.3), then asked the list if it could be a drbd issue, but in the 
end the kernel that came with 5.4 was at fault.

The only issues I saw with the ext4 code on the 5.3 RHEL kernels was 
that it had issues deleting files (this is independent of drbd). With 
the new 5.4 kernels (where ext4 is based on a much fresher ext4 kernel 
code) the issues were gone.

The benchmarks for ext4 over ext3 and the ability to run fsck without 
having to check all empty space where the deciding factors for me 
originally until I decided to revert back to ext3 for the sake of using 
the proven file system (which I regret a bit now that my system is in 
production, but I can change again on a long weekend). If you use a 
distro which runs an even newer kernel (as compared to RHEL 5.x), you 
will most likely have a very stable ext4 file system.

In case anybody hits the nfs kernel bug for RHEL5.4, here is the 
bugzilla entry (ranting included ;):



Tim O'Donovan wrote:
> Hi List,
> Does anyone have any experience with ext4? I'm in the process of putting
> together some plans for a 2TB, RAID 10 backed, 2 node DRBD cluster to
> run an NFS based file server, and I'm trying decide whether to stick
> with ext3 or take the plunge into the world of ext4. The file server
> will be the backend for a cluster of mail servers.
> Any advice would be appreciated.
> Thanks,
> Tim
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> drbd-user at lists.linbit.com
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