From mboxrd@z Thu Jan 1 00:00:00 1970 From: Loic Dachary Subject: Re: Reliability models Date: Wed, 15 Jan 2014 00:44:13 +0100 Message-ID: <52D5CBCD.5000608@dachary.org> References: <52D3A85E.4050301@dachary.org> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="F7X3Fn04ojo4nDWm5Ax57khrgvd5Oj43m" Return-path: Received: from smtp.dmail.dachary.org ([91.121.254.229]:43552 "EHLO smtp.dmail.dachary.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750880AbaANXoQ (ORCPT ); Tue, 14 Jan 2014 18:44:16 -0500 In-Reply-To: Sender: ceph-devel-owner@vger.kernel.org List-ID: To: Kyle Bader Cc: Ceph Development This is an OpenPGP/MIME signed message (RFC 4880 and 3156) --F7X3Fn04ojo4nDWm5Ax57khrgvd5Oj43m Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable Crystal clear, thanks ! On 13/01/2014 18:25, Kyle Bader wrote: > Hi Loic, >=20 >> IIRC you figured out how to use https://github.com/ceph/ceph-tools/tre= e/master/models . Do you happen to have some kind of HOWTO or even the li= st of commands you've used to get me started ? >=20 > git clone ...ceph-tools > cd ceph-tools/models/reliability > ./main.py -g >=20 > At this point a graphical form should pop up and most of it should be > straight forward. NRE rate is non recoverable read errors, the NRE > model determines how an array/disk responds to a non recoverable read > error event. I tend to be on the conservative end having seen my share > of RAID horror shows so I set the NRE model to "fail". The other > gotcha is most disk manufacturers use MTBF or AFR while the > reliability modeling tool requests FITS. The formula you will need is: >=20 > MTBF =3D 1,000,000,000 x 1/FIT. [1] >=20 > Stripe length is the number of RADOS objects that are require to store > a blob of data, ie all RADOS objects that compose a RBD volume. Since > this code was written a while ago there is no code to support modeling > erasure coded objects. If you have any questions, let me know! >=20 > [1] http://en.wikipedia.org/wiki/Failure_rate#Units >=20 --=20 Lo=EFc Dachary, Artisan Logiciel Libre --F7X3Fn04ojo4nDWm5Ax57khrgvd5Oj43m Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.20 (GNU/Linux) Comment: Using GnuPG with Thunderbird - http://www.enigmail.net/ iEYEARECAAYFAlLVy80ACgkQ8dLMyEl6F209WgCgikYfAoPw9f4AoutILZvIBJEf oUUAniZUw6N2Tdr/hyeFx2d656z2cLl8 =rsK3 -----END PGP SIGNATURE----- --F7X3Fn04ojo4nDWm5Ax57khrgvd5Oj43m--