io-threads (was Re: [Gluster-devel] write-behind mtime workaround)

Brent A Nelson brent at
Fri Apr 27 23:06:17 UTC 2007

Hmm, it looks like io-threads is responsible for more than just mtime 
glitches when used with write-behind.  I just found that the problems I 
had with NFS re-export go away when I get rid of io-threads (plus, now 
that I can enable write-behind, the NFS write performance is far better, 
by at least a factor of 5)!

It looks like I'll be switching off io-threads for now, and turning on all 
the other performance enhancements.



On Fri, 27 Apr 2007, Brent A Nelson wrote:

> On Thu, 26 Apr 2007, Anand Avati wrote:
>> Brent,
>> I understand what is happening. It is because I/O threads lets the
>> mtime overtake the write call. I assume you have loaded io-threads on
>> server side (or below write-behind on client side).
> Yes, I have io-threads loaded on the server.  This occurs when I load 
> write-behind on the client.
>> I could provide you a temporary 'ugly' fix just for you if the issue is 
>> critical (until the proper framework comes in 1.4)
> It would be worthwhile if the temporary fix is acceptable for the 1.3 release 
> (otherwise, you'll need a warning included with the release, so that people 
> enabling io-threads and write-behind know what to expect), but don't waste 
> your time if it's just for me.  Push on to 1.4 and the real fix; I'll just 
> leave write-behind disabled for now.
> Many Thanks,
> Brent

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