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From Kristian Waagan <krist...@apache.org>
Subject Re: Derby Database Corruption Issues
Date Wed, 12 Jul 2017 19:02:37 GMT
Hi Shreyans,

I believe this is still valid advice, but the details depend on your
IO-system, your operating system and your server hardware.

The issue here is that Derby is told the data has been written to stable
storage, but then it has in fact not. If the machine crashes at this point
data may be lost.
For instance, if you are using a SAN there is typically a battery / UPS
backed buffer (or other types of buffers that don't loose data in case of a
power outage) on the "storage side", but for this to be useful you must
ensure data is pushed through the IO driver and is not buffered locally by
the operating system.

Using asynchronous writes is a typical way of obtaining better [write]
performance. In many cases the downside is a higher chance of data
corruption.
This may or may not be acceptable for your application.


Regards,
-- 
Kristian

Den ons. 12. jul. 2017, 20:04 skrev Shreyans Jain <shreyans2799@gmail.com>:

> I was reading https://wiki.apache.org/db-derby/DatabaseCorruption and i
> found prevention of corruption which states
> "Switch off the machine's write caching" . now the article is written in
> 2013. Is it still application to derby database corruption or now it has no
> effect.
>
> Regards,
> Shreyans Jain
>

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