From mboxrd@z Thu Jan 1 00:00:00 1970 From: Francis Moreau Subject: Re: bcache and SSD over provisioning Date: Wed, 13 Nov 2013 20:51:55 +0100 Message-ID: <5283D85B.10904@gmail.com> References: Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-15 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: In-Reply-To: Sender: linux-bcache-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Matthew Patton , linux-bcache-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: linux-bcache@vger.kernel.org Hello Matthew, Le 13/11/2013 15:13, Matthew Patton a =E9crit : > On Wed, 13 Nov 2013 03:42:54 -0500, Francis Moreau =20 > wrote: >=20 >> First I'd like to know if over-provisioning is still needed when >> bcache is used ? >=20 > it's needed for any decent, sustained write load if you don't want =20 > performance to crash thru the floor. But it doesn't sound like this i= s =20 > your use case. Are you sustaining 5000+ write IOPs? >=20 That's indeed not really required: my system is for a desktop usage. >> - Should I create 2 partitions with one left emtpy and whose size = is >> roughly 7% of the device size ? >=20 > Your SSD already has 7% overprovisioning. For best sustained and =20 > consistent write performance you'll want to bump it to 25-30%. Yes yo= u =20 > just need to partition/LVM down to the desired size. Hmm, I don't see what makes you think that my SSD has already 7% overprovisioning ? Actually I don't think it's the case. Thanks for your help.