[CentOS] how to find source of data loss / corruption

[anax]

Hi Rudi
we once had a similar problem on a Web:

This Web had this in particular that its home-page needed to be deleted 
daily and of course reinstalled immediately.
Then, in a new version of the Web it did not need this delete/reinstall 
cycle any more, so the webadmin just removed the link to the delete 
script. He did not remove the delete-script itself from the Web.
The effect was, that the home-page was still deleted at random times.

What we then found out: We used an internal Search-Engine which crawled 
this web. And this Search-Engine had not forgotten the link to the 
delete-script, but invoked it at random times, whenever it crawled  the 
particular Web.

Your case: could it be something similar?

suomi

On 2011-12-15 11:28, Rudi Ahlers wrote:
> Hi,
>
> 2 websites, hosted on 2 different CentOS 5.7 servers (one being very
> new, about 3 weeks old) keeps loosing data - but it's more like it's
> corrupted than being deleted.
>
> For example, a photo would be uploaded last night and today when we
> checked it, it doesn't show on the website. So we check if the file is
> on the server, and exists but is 0KB in size. Last night it still
> worked fine. The photo is 482Kb in size.
>
> The first time this happened we thought it was due to a bug with
> CentOS 5.7 + EXT4 + quotas (there's a bug open for this) and since the
> server's console kept giving errors about possible data corruption we
> thought it would be best if we move everything to a more stable
> platform. So we brought a new server, setup CentOS 5.7 + ext3 + quotas
> (which has been working fine on all our servers for a long time) and
> moved the data across. A few days down the line and I still see this
> happening.
>
> I'm out of ideas and hope someone could shed some light on the matter.
> I've checked some suggested search results, but couldn't find any
> issues with the HDD according to SMART. The servers' both have 4GB RAM
> and 8Core CPU's.Neither RAM, nor CPU usage is high. Both are setup
> with RAID10 across 4 entrerprise HDD's, one server has software RAID
> and the new one hardware RAID. So even when we changed the RAID
> subsystem it still happens.
>
>
>