[Dovecot] XFS vs EXT4 for mail storage

[Charles Marcus]

Thanks for the replies...

On 2013-05-02 7:54 AM, Luigi Rosa <lists at luigirosa.com> wrote:
> The I/O cascading is in essence the muptiplying factor of each disk write at
> application level. Consider a SQL UPDATE statement: you have date written on
> database and trasaction log. Each file will have its mtime updated. If the
> underlying file system is transactional you will have double writes for actual
> file and transaction log... And so on.

Well, this is purely for a mailstore. The only thing I use SQL for is my 
userdb, so 99.999% of that is just reads for user validation and user 
auth. Writes are only very occasional, and tiny when they happen, so 
basically no impact on the system.

On 2013-05-02 8:04 AM, Alessio Cecchi <alessio at skye.it> wrote:
> My mount options are:
>
> "rw,noatime,attr2,delaylog,nobarrier,inode64,noquota"

Hmmm... some questions...

man mount doesn't show delaylog, nobarrier or noquota as valid mount 
options... ?

But, assuming they are, since rw is the default for all fs types, and 
attr2 is default for xfs, I could accomplish the same with:

defaults,noatime,delaylog,nobarrier,inode64,noquota

I'm not using quotas, and understand what inode64 does and am fine with 
that, but what I'm still unsure of for a VM environment is the delaylog 
and nobarrier options.

Are these recommended/optimal for a VM? Running on ESXi (does it matter 
what hypervisor ie being used)?

-- 

Best regards,

Charles