From mboxrd@z Thu Jan 1 00:00:00 1970 References: <42E7ED35-B32E-4C02-976A-7A9E5380EEA8@mac.com> From: Zdenek Kabelac Message-ID: Date: Thu, 14 Sep 2017 11:37:21 +0200 MIME-Version: 1.0 In-Reply-To: Content-Language: en-US Content-Transfer-Encoding: 8bit Subject: Re: [linux-lvm] Performance penalty for 4k requests on thin provisioned volume Reply-To: LVM general discussion and development List-Id: LVM general discussion and development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , List-Id: Content-Type: text/plain; charset="utf-8"; format="flowed" To: LVM general discussion and development , Dale Stephenson Dne 14.9.2017 v 11:00 Zdenek Kabelac napsal(a): > Dne 14.9.2017 v 00:39 Dale Stephenson napsal(a): >> >>> On Sep 13, 2017, at 4:19 PM, Zdenek Kabelac wrote: >>> >> >> md127 is an 8-drive RAID 0 >> >> As you can see, there’s no lvm striping; I rely on the software RAID >> underneath for that.  Both thick and thin lvols are on the same PV. >>> >>> SSD typically do needs ideally write 512K chunks. >> >> I could create the md to use 512k chunks for RAID 0, but I wouldn’t expect >> that to have any impact on a single threaded test using 4k request size.  Is >> there a hidden relationship that I’m unaware of? > > > Yep - it seems the setup in this case is the best fit. Sorry my typo here - is NOT ;) Zdenek