Re: [FAQ-answer] Re: soft RAID5 + journalled FS + power failure = problems ?

[mauelsha]

"Stephen C. Tweedie" wrote:
> 
> Hi,
> 
> This is a FAQ: I've answered it several times, but in different places,

<SNIP>

> THIS IS EXPECTED.  RAID-5 isn't proof against multiple failures, and the
> only way you can get bitten by this failure mode is to have a system
> failure and a disk failure at the same time.
> 

To try to avoid this kind of problem some brands do have additional
logging (to disk
which is slow for sure or to NVRAM) in place, which enables them to at
least recognize
the fault to avoid the reconstruction of invalid data or even enables
them to recover
the data by using redundant copies of it in NVRAM + logging information
what could be
written to the disks and what not.

Heinz