[mythtv-users] CentOS vs Fedora, RAID vs LVM

[Bill Williamson]

On 30/03/2009, at 11:46 AM, David Brodbeck <gull at gull.us> wrote:

> Bobby Gill wrote:
>> I do recall reading something about XFS being  dangerous if your  
>> box goes off in a power outage or something similar, I'm curious if  
>> that applies to JFS as well?
>
> There are rumors to that effect, but I've never seen it happen.  I  
> think they're are based on the fact that XFS only guarantees the  
> filesystem's integrity, not the data integrity of files that are  
> open for write when the power fails.  This is because it only  
> journals metadata.  The upshot is, there's a chance that a file open  
> for write during a power outage will end up corrupted or zeroed  
> out.  This is not unique to XFS.  Most journaling filesystems work  
> this way, because journaling all data has a large performance impact.
>
> I've used XFS for many years and always found it to be very stable.
>
> The only major caveat with XFS is that XFS+LVM+mdadm can cause  
> problems on kernels with 4K stacks.  I can't comment on this because  
> I don't use all three together.
>
> One limitation of XFS that you may find important, if you're using  
> LVM, is that XFS filesystems cannot shrink -- they can only grow.   
> ext3, on the other hand, can be resized in either direction.
>
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Xfs (and ext4!!!) have a long default commit time. This improves  
performance, but means you can lose files in programs written without  
fflush calls if you crash between the file being written and it  
actually commiting.