Gluster users - Nov 2015 - File Corruption with shards - 100% reproducable

On 19/11/15 14:49, Krutika Dhananjay wrote:
> I wanted to ask you one more thing: specifically in VM workload with 
> sharding, do you run into consistency issues with 
> strict-write-ordering being off?
> I remember suggesting that this option be enabled. But that was for 
> plain dd on the mountpoint (and not inside the vm), where it was 
> necessary.
> I want to know if it is *really* necessary in VM workloads.

Hi Krutika, sorry for the delay, have been head down with work and sick 
doggies :(

No I didn't need strict-write-ordering off/on, the VM's were fine. It 
was only stat-prefetch that needed to be off.

One caveat - I started testing with 3.7.5, then upgraded to 3.7.6, but 
didn't upgrade the op-version (always forget that).

Once I set the op version to 3.7.6 sharded volumes started reporting 
correct file sizes (for new files) even with strict-write-ordering off. 
However disk usage was still out by a lot.

On 20/11/15 15:15, Lindsay Mathieson wrote:
> One caveat - I started testing with 3.7.5, then upgraded to 3.7.6, but 
> didn't upgrade the op-version (always forget that).
>
> Once I set the op version to 3.7.6 sharded volumes started reporting 
> correct file sizes (for new files) even with strict-write-ordering 
> off. However disk usage was still out by a lot. 
Ignore that, I just retested and file sizes (ls -l) were wildly out.

However the VM still migrates between nodes with with 
strict-write-ordering off, no problems.

My apologies for the confusion.