Expireover running really slow

[Kirill Berezin]

*Hie.*
This is a real problem for running innd with large storages. Performance 
degrades because overview records are highly scattered over big area, 
ovdb does not help. An expiration for ovdb works much faster for first 
couple of weeks, but later it will be slower an slower. Fortunately a 
separate expiration index can help, but no such feature available and 
implementation requires a lot of changes for existing code. It seems a 
best solution for a moment is to use buffindexed method and to use as 
much as possible separate physical drives for overview storage.

kirill


Kristian Grønfeldt Sørensen wrote:
> Hi.
>
> I've set up a new inn server as a replacement for our old one. The
> server is running inn 2.4.3-1 from Debian stable.
> My problem is that expireover is taking approximately 16 hours to
> finish. I find this quite strange as the new server is more powerful
> than the old one, which did not have this problem. 
>
> Since the new server has more disk space, there will be more articles
> stored in the spool, but the old server can finish expireover within an
> hour or so. 
>
> My setup is:
>
> article-spool and overview files is on two separate LVM logical volumes
> with XFS on top of them. All articles are stored in a total of 280 CNFS
> buffers. 
> Overview is buffindexed in a total of 82 files.
> The LVM volumes is hosted on a 4-disk RAID-5 array on an Intel SRCS28X
> sata controller. Benchmarking with bonnie++ on this device reveals read
> speeds of around 140 MB/s and write speeds of around 110 MB/s, so the
> underlying hardware should not be any problem.
>
> However during expireover the box spends ~60% if its time in IOWait
> mode, which indicates to me that the problem is related to the disk
> device.
>
> Using iostat, I can see that constant reading of approximately 1MB/s
> and, and almost no write requests. The LV hosting the article spool has
> almost no reads but around 1 MB/s but in a very bursty fashion - always
> 4 MB at a time. 
>
> Does any of you have any ideas for optimizing expireover performance for
> this system? I've tried playing around with readahead-policies and
> enabling/disabling write caching with no result.
>
> Regarde
>
> Kristian Sørensen
>