From mboxrd@z Thu Jan 1 00:00:00 1970 From: Loic Dachary Subject: Re: osd pool erasure code stripe width Date: Sat, 20 Jun 2015 08:27:23 +0200 Message-ID: <558507CB.4080303@dachary.org> References: <55849BF7.5050603@dachary.org> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="vBvv1BMDoG8dbQ7fUk5iX9jTfkWTUsW24" Return-path: Received: from mail2.dachary.org ([91.121.57.175]:37301 "EHLO smtp.dmail.dachary.org" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751122AbbFTG13 (ORCPT ); Sat, 20 Jun 2015 02:27:29 -0400 In-Reply-To: Sender: ceph-devel-owner@vger.kernel.org List-ID: To: "Deneau, Tom" , ceph-devel This is an OpenPGP/MIME signed message (RFC 4880 and 3156) --vBvv1BMDoG8dbQ7fUk5iX9jTfkWTUsW24 Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: quoted-printable Hi Tom, On 20/06/2015 03:18, Deneau, Tom wrote: > So if I am looking at the performance of a system with > ceph_erasure_code_benchmark, does this mean I should concentrate > on the performance with --size 4096 (or whatever stripe width my > ec pools are going to use)? Yes. But the erasure code plugin encoding speed is not the only factor. Y= ou probably want to try a rados bench instead to get more realistic numbe= rs. Cheers >=20 > -- Tom >=20 >> -----Original Message----- >> From: Loic Dachary [mailto:loic@dachary.org] >> Sent: Friday, June 19, 2015 5:47 PM >> To: Deneau, Tom; ceph-devel >> Subject: Re: osd pool erasure code stripe width >> >> Hi Tom, >> >> A stripe width of 4KB (the default) means the object is encoded 4KB at= a >> time. It does not show in the file written to disk. >> >> Cheers >> >> On 19/06/2015 22:11, Deneau, Tom wrote: >>> I am trying to understand the use of "osd pool erasure code stripe wi= dth" >>> For example, I have a single-node system with a k=3D2,m=3D1 ec pool a= nd I >>> write a single 40M object to this pool using rados bench. >>> But when I look on the disk, I still see only the 3 20M pieces for th= is >> object. >>> Where does the striping get used? >>> >>> -- Tom Deneau, AMD >>> >>> >>> Description: >>> Sets the desired size, in bytes, of an object stripe on every erasure= coded >> pools. Every object if size S will be stored as N stripes and each str= ipe >> will be encoded/decoded individually. >>> Type: >>> Unsigned 32-bit Integer >>> Default: >>> 4096 >>> >>> >>> -- >>> To unsubscribe from this list: send the line "unsubscribe ceph-devel"= >>> in >>> >> >> -- >> Lo=EFc Dachary, Artisan Logiciel Libre >=20 --=20 Lo=EFc Dachary, Artisan Logiciel Libre --vBvv1BMDoG8dbQ7fUk5iX9jTfkWTUsW24 Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.22 (GNU/Linux) iEYEARECAAYFAlWFB8sACgkQ8dLMyEl6F23UBgCgnPMDGW3uXaA21MtpTYhtQ3UM Ok4AniMBkkvxFY9sirNbGu09/5GaMwlJ =TdK/ -----END PGP SIGNATURE----- --vBvv1BMDoG8dbQ7fUk5iX9jTfkWTUsW24-- -- To unsubscribe from this list: send the line "unsubscribe ceph-devel" in