Date: Wed, 22 Aug 2012 17:28:04 +0200 From: Mark Martinec <Mark.Martinec+freebsd@ijs.si> To: freebsd-fs@freebsd.org Subject: Re: `zpool create' fails on geli ... Message-ID: <201208221728.04712.Mark.Martinec%2Bfreebsd@ijs.si> In-Reply-To: <20120822132905.GA53612@wonko.batmule.dk> References: <20120821190742.54449@relay.ibs.dn.ua> <20120822123535.0385f118@fabiankeil.de> <20120822132905.GA53612@wonko.batmule.dk>
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> Fabian Keil wrote:
> > Zeus Panchenko <zeus@ibs.dn.ua> wrote:
> > > geli init -K /path/key -s 4096 -e aes-xts /dev/adaX
> >
> > Does your disk actually use 4k sectors? Otherwise it's not clear
> > to me that "-s 4096" makes sense when using ZFS.
> >
> > I'm not claiming that it's obviously wrong, but I'm not aware of
> > any benchmarks that show that it's better than the default in
> > any way.
It benefits geli performance (tried it, it does):
$ man geli
-s sectorsize Change decrypted provider's sector size.
Increasing sector size allows to increase per-
formance, because we need to generate an IV
and do encrypt/decrypt for every single sector
- less number of sectors means less work to
> It is my understanding that creating a 4K setup will prepare you
> for the day when your replacement drive is a 4K one.
> No benefit today, but also no real performance hit. And we avoid
> a real performance hit later.
That day has already arrived some time ago.
For ZFS on WD20EARS disks, persuading ZFS to use 4k sectors
makes a significant performance boost.
Mark
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